KR20200094083A - Manufacturing method of laminate - Google Patents

Abstract

A method of manufacturing a laminate comprising an adherend and an adhesive piece partially covering the adherend, wherein the adhesion strength of the adhesive piece to the adherend is 5N/25mm or more is provided. The laminate manufacturing method includes cutting process of attaching an adhesive sheet to the adherend, and cutting at the boundary between the first region constituting the adhesive piece and the second region not constituting the adhesive piece of the adhesive sheet. It includes a cut process to be performed, and a partial removal process in which the second region is peeled off from the adherend while leaving the first region on the adherend in this order. Here, the partial removal process is performed before the adhesive strength of the adhesive sheet to the adherend exceeds 2N/25 mm.

Description

Manufacturing method of laminates {MANUFACTURING METHOD OF LAMINATE}

The present invention relates to a method for manufacturing a laminate.

This application claims priority based on Japanese Patent Application No. 2017-253311 filed on December 28, 2017, and the entire contents of the application are incorporated herein by reference.

According to the laminate partially covered with the adhesive piece by attaching one or two or more adhesive pieces to the adherend, various patterns can be expressed according to the appearance or arrangement of the pressure-sensitive adhesive. As a method of manufacturing a laminate in which the adherend is partially covered with an adhesive piece with high precision, the adhesive sheet is pre-cut in the shape of a desired adhesive piece, such as a coverlay film bonding of a circuit board, and the adhesive piece is adhered. The method of aligning and attaching the position to is generally used. Patent document 1 is mentioned as a technical document regarding this kind of technology.

Japanese Patent Application Publication 2013-38379

However, in the above-described method, since the adhesive sheet is previously cut into the shape of a desired adhesive piece, and then subjected to position alignment to join to a predetermined adherend site, errors in both the cutting precision and the bonding precision occur. For this reason, it is feared that very expensive equipment will be required in order to manufacture a product with high yield in the manufacture of electronic components that will be miniaturized and refined in the future. In addition, for example, in the case where the size of the cut adhesive piece is large, or the shape is complicated, it may be more difficult to attach the adhesive piece to the adherend with high positional accuracy and shape accuracy. Particularly, when a strongly adhesive pressure-sensitive adhesive piece is used to produce a highly durable laminate, the difficulty of the operation of accurately attaching the pressure-sensitive adhesive piece to the adherend tends to increase.

Therefore, it is an object of the present invention to provide a method for efficiently manufacturing a laminate in which a pattern by an adhesive piece is formed on an adherend with high precision and the adhesive piece is firmly bonded to the adherend. Another related invention is to provide an apparatus suitable for carrying out such a manufacturing method.

According to the present specification, a method of manufacturing a laminate comprising an adherend and an adhesive piece partially covering the adherend, wherein the adhesion strength of the adhesive piece to the adherend is 5N/25mm or more is provided. The laminate manufacturing method includes a sticking step of attaching a pressure-sensitive adhesive sheet comprising a base material layer and a pressure-sensitive adhesive layer laminated on at least the side of the substrate to the adherend, and the pressure-sensitive adhesive piece in the pressure-sensitive adhesive sheet. A cutting process of cutting at the boundary between the first region constituting and the second region not constituting the adhesive piece, and peeling the second region from the adherend while leaving the first region on the adherend Some removal processes to be removed are included in this order. Here, the partial removal process is performed before the adhesive strength of the adhesive sheet to the adherend exceeds 2N/25 mm.

According to the said manufacturing method, the structure by which the 1st area|region was arrange|positioned with the shape precision and position high precision on an adherend can be obtained efficiently by performing the said attaching process, the said cutting process, and the said partial removal process in this order. In addition, since the partial removal process is performed before the adhesive strength of the pressure-sensitive adhesive sheet to the adherend exceeds 2N/25mm, it is easy to perform the operation of peeling the second region from the adherend, and also the deformation or damage of the adherend It is difficult to occur.

In some embodiments, as the above-mentioned pressure-sensitive adhesive sheet, those having an adhesive strength of 2 N/25 mm or less after 24 hours at 23° C. after bonding to polyimide can be preferably used. According to such an adhesive sheet, it can respond flexibly to the lead time of the manufacturing process of a laminated body.

In some aspects of the method of manufacturing a laminate disclosed herein, the heat treatment is performed after the partial removal step to set the adhesive force of the first region to the adherend to be 5 N/25 mm or more. Such an aspect uses, for example, an adhesive sheet having a pressure-sensitive adhesive layer comprising a polymer A having a glass transition temperature of less than 0° C. and a polymer B which is a copolymer of a monomer having a polyorganosiloxane skeleton and a (meth)acrylic monomer. Although it can implement, it is not limited to this.

In some other aspects of the method for manufacturing a laminate disclosed herein, after the partial removal step, an ultraviolet irradiation treatment is performed so that the adhesive force of the first region to the adherend is 5 N/25 mm or more. This aspect is made of, for example, a photocurable composition comprising a base polymer and a photocuring agent, wherein the photocuring agent is a polyfunctional (meth)acrylate, and the content of the photocuring agent is 1 part by weight based on 100 parts by weight of the base polymer. Although it can implement using an adhesive sheet provided with the adhesive layer which is 50 weight part or more and weight part or less, it is not limited to this.

In addition, the method of manufacturing a laminate disclosed herein may be carried out in an embodiment where the adhesive force to the adherend in the first region is 5 N/25 mm or more after the partial removal step, and stored at room temperature.

In addition, in this specification, normal temperature means the temperature of about 0 degreeC-35 degreeC, typically 10 degreeC-35 degreeC, when it does not mention.

In some embodiments, as the pressure-sensitive adhesive sheet, one having a thickness of 30 µm or more and having a thickness Ts of the base material layer that is twice or more the thickness Ta of the pressure-sensitive adhesive layer can be preferably used. By using such an adhesive sheet, the advantage that it is easy to perform affixing operation to a to-be-adhered body or a peeling operation of a second region is obtained.

It is preferable that the second region is set such that at least one end thereof reaches the end of the adhesive sheet. Thereby, the advantage that it is easy to pick up a 2nd area when performing the said partial removal process is obtained. The second region may have a shape in which one end leading to the end of the pressure-sensitive adhesive sheet is widened toward the edge of the pressure-sensitive adhesive sheet from the viewpoint of improving pickup properties.

The manufacturing method disclosed herein can be preferably carried out in an aspect in which the pressure-sensitive adhesive sheet having an area of 2500 cm 2 or more and a length of a short side of 50 cm or more is used in the pasting step. In the aspect of using the adhesive sheet having such a large area and a large width, the advantage by employing the manufacturing method disclosed herein can be more effectively exhibited.

The manufacturing method disclosed herein is a step performed after the sticking step using a plurality of units corresponding to the laminate as the sticky sheet and the adherend used in the sticking step, and the sticking step is described above. The dividing step of dividing the sheet and the adherend into the units may be further included. As described above, a plurality of laminates can be efficiently manufactured by dividing the adhesive sheet comprising a plurality of units after attaching it to the adherend. In addition, the structures of the plurality of units may be the same or different.

According to this specification, an apparatus for manufacturing a laminate comprising an adherend and an adhesive piece partially laminated on the adherend is provided. The apparatus includes a sticking mechanism for sticking the adhesive sheet. In addition, the apparatus may include a cutting mechanism for cutting the adhesive sheet. In addition, the device may include a peeling mechanism for peeling the second region. Using the manufacturing apparatus having such a configuration, any of the laminate manufacturing methods disclosed herein can be suitably carried out.

In addition, the appropriate combination of each of the above-described elements may also be included in the scope of the invention to seek protection by a patent by patent application.

1 is a flowchart showing a method of manufacturing a laminate according to an embodiment.
2 is a perspective view showing a laminate produced by the method for manufacturing a laminate according to one embodiment.
3 is a sectional view taken along line III-III in FIG. 2.
4 is a perspective view for explaining a cut process of a method for manufacturing a laminate according to one embodiment.
It is explanatory drawing which shows schematic structure of the laminated body manufacturing apparatus used for the laminated body manufacturing method which concerns on one Embodiment.
6 is an explanatory diagram showing a method for performing a durability test.

Hereinafter, suitable embodiments of the present invention will be described. Matters other than those specifically mentioned in the present specification and matters necessary for the practice of the present invention may be understood by those skilled in the art based on the technical common knowledge at the time of teaching and filing for the practice of the invention described in the present specification. This invention can be implemented based on the content disclosed in this specification and common knowledge in the field.

In addition, in the following drawings, the same reference numerals are given to members and parts that exhibit the same action, and overlapping explanations may be omitted or simplified. Note that the embodiments described in the drawings are schematically illustrated to clearly describe the present invention, and do not necessarily accurately represent actual sizes and scales.

<<Method of manufacturing a laminate>>

1 is a flowchart showing a method for manufacturing a laminate according to an embodiment, FIG. 2 is a perspective view showing a laminate produced by the method, and FIG. 3 is a cross-sectional view taken along line III-III. 2 and 3, the laminate 1 manufactured by this embodiment includes an adherend 10 and an adhesive piece 21A partially covering the surface 10A of the adherend 10 , 21B). The adhesive pieces 21A, 21B attach the adhesive sheet 20 to the adherend 10, and then leave the first region 21 of the adhesive sheet 20 on the adherend 10 to form the second region By removing and removing (22) from the adherend 10, it is formed from the first region 21 left on the adherend 10. The pressure-sensitive adhesive sheet 20 has a configuration in which the pressure-sensitive adhesive layer 204 is laminated on one surface of the base material layer 202.

The method for manufacturing a laminate according to this embodiment includes, as shown in FIG. 1, a sticking step S10, a cutting step S20, and a partial removing step S30 in this order.

In the pasting process S10, the adhesive sheet 20 is stuck to the adherend 10. The pressure-sensitive adhesive sheet 20 used in this step is composed of the first region 21 and the laminated region 1, which are regions included in the components of the laminate 1 as the adhesive pieces 21A and 21B. It comprises a second region 22 which is not an element and is used only in the manufacturing process of the laminate 1. In the example shown in FIG. 2, the second region 22 extending linearly from one end in the longitudinal direction of the pressure-sensitive adhesive sheet 20 to the other end is set at almost the center of the width of the pressure-sensitive adhesive sheet 20. . In the pressure-sensitive adhesive sheet 20 used in the attaching step S10, the first region 21 and the second region 22 are physically connected, and these regions 21 and 22 are treated as a series of pressure-sensitive adhesive sheets 20. Can.

In the cutting process S20, cutting is performed at the boundary between the first region 21 and the second region 22 of the pressure-sensitive adhesive sheet 20 attached to the adherend 10. For example, as shown in FIG. 4, laser cutting is performed to irradiate the laser light L along the cutting line C that forms the boundary between the first region 21 and the second region 22. Further, although Fig. 4 shows an example of laser cutting, the means for cutting is not particularly limited, and can be appropriately selected depending on the purpose or use among various known cutting means. Examples of such cutting means include laser cutting using laser light such as a CO ₂ laser or a YAG laser; Cutting by cutting blades such as Thompson blades, pinnacle blades, rotary blades, knives; Blade cutting; And the like, but are not limited to these. The cutting means can be used alone or in combination of two or more.

In part of the removal process S30, in the pasting step, before the adhesive strength of the pressure-sensitive adhesive sheet adhered to the adherend to the adherend exceeds 2N/25mm (in other words, after adhesion, the adhesion force is suppressed to 2N/25mm or less. ) Is done. In this partial removal process S30, the second region 22 is peeled off from the adherend 10 while leaving the first region 21 on the adherend 10. For example, the second region 22 is extended from one end in the long side direction of the pressure-sensitive adhesive sheet 20 toward the other end. As a result, as shown in Figs. 2 and 3, the adhesive pieces 21A and 21B formed from the first region 21 are disposed on the adherend 10 spaced apart from each other, and the adhesive pieces 21A and 21B are arranged. A structure in which the adherend 10 is exposed is formed between them.

In the method for manufacturing a laminate according to this embodiment, after affixing the adhesive sheet 20 to the adherend 10, a part of the adhesive sheet 20, that is, the second region 22 is peeled from the adherend 10 By removing, a coating pattern comprising two pieces of adhesive pieces 21A, 21B spaced apart from each other is formed on the adherend 10. According to this method, the first region 21 constituting the two adhesive pieces 21A, 21B spaced apart from each other in the laminate 1 is adhered 10 in the form of one adhesive sheet 20. ), and the adjustment of the relative positional relationship between the pressure-sensitive adhesive piece 21A and the pressure-sensitive adhesive piece 21B at the time of attachment of the pressure-sensitive adhesive sheet 20 becomes unnecessary, thereby improving the manufacturing efficiency of the laminate 1 do. In addition, since the adhesive sheet 20 is adhered to the adherend 10, the first region 21 and the second region 22 of the adhesive sheet 20 are subjected to a cutting process, so that the first region ( It is easy to increase the shape accuracy of 21) and the positional accuracy with respect to the adherend 10. For example, in the pasting step S10, when a slight misalignment occurs in the sticking position of the adhesive sheet 20 with respect to the adherend 10, or due to temperature change or release of internal stress, the adhesive sheet 20 may be slightly Even when stretching or deformation occurs, their influence can be eliminated or reduced by adjusting the position and shape of the cutting process in the cutting step S20.

In the above manufacturing method, the laminate 1 having an adhesive force of the adhesive pieces 21A, 21B to the adherend of 5N/25mm or more is produced. Thus, the adhesive pieces 21A, 21B are firmly bonded to the adherend 10, when using the laminate 1, external forces such as human hands contacting, deformation of the adherend, or lamination It is preferable from the viewpoint of suppressing the thought that the adhesive pieces 21A, 21B are peeled off or floated from the adherend 10 due to environmental factors such as the sieve being exposed to weather or temperature changes. On the other hand, in some removal steps S30, if the adhesiveness of the second region 22 to the adherend 10 is too high, deformation or surface of the second region 22 at the time of peeling of the adherend 10, such as elongation, etc. Problems such as peeling may occur, or the second region 22 may be cut off during peeling. According to the above manufacturing method, in the attaching step S10, the adhesive pieces 21A and 21B are avoided by performing a part of the removing step S30 before the adhesive force to the adherend of the adhesive sheet adhered to the adherend exceeds 2N/25mm. The laminate 1 tightly bonded to the complex 10 can be produced, and the above-described problem can be avoided or alleviated in some removal step S20.

In some embodiments, the adhesive force A _P of the pressure-sensitive adhesive sheet to the adherend during the partial removal step may be less than 2N/25mm, for example, from the viewpoint of ease of peeling of the second region, and may be 1.5N/25mm It may be less than, may be 1.3 N/25 mm or less, 1 N/25 mm or less, or 0.8 N/25 mm or less. The lower limit of the adhesive force A _P is not particularly limited, but may be, for example, 0.005 N/25 mm or more, or 0.01 N/25 mm or more, from the viewpoint of suppressing the displacement or lifting of the first region in the cutting process or the partial removal process. It may be 0.05N/25mm or more, 0.1N/25mm or more, or 0.2N/25mm or more.

The manufacturing method disclosed herein can be preferably carried out using a pressure-sensitive adhesive sheet having 2N/25mm or less adhesive strength (hereinafter, also referred to as adhesive strength after 24 hours at room temperature) after 24 hours at 23°C after bonding to polyimide. . According to such an adhesive sheet, it can respond flexibly to the lead time of the manufacturing process of a laminated body. The upper limit of the adhesive force after 24 hours at room temperature may be, for example, the same as any upper limit of the adhesive force A _P exemplified above. The lower limit of the adhesive force after 24 hours at room temperature may be, for example, the same as any lower limit of the adhesive force A _P exemplified above.

After performing some removal process S30, you may further perform the adhesive force increase process S40 which increases the adhesive force of the adhesive pieces 21A, 21B with respect to the adherend 10 as needed. According to the manufacturing method including such an adhesive force increase process, the period until the target laminated body (that is, the laminated body whose adhesive force with respect to the to-be-adhered body of an adhesive piece is 5N/25mm or more) can be shortened. Thereby, productivity of a laminated body can be improved. In addition, by performing the above-mentioned adhesive strength increasing step, there is a tendency that a laminate having a higher adhesive strength to the adherend of the adhesive piece is produced.

The adhesive strength increasing step S40 may be a step of applying a stimulus that promotes an increase in the adhesive strength of the adhesive pieces 21A and 21B. The content of the stimulus can be appropriately selected depending on the type of adhesive sheet to be used and the like. Examples of the stimulus may include heating, irradiation with actinic rays, press (pressing), and the like. These stimuli can be applied alone or in combination of two or more.

In addition, in the method of manufacturing a laminate disclosed herein, the process of increasing the adhesive strength is not an essential process, considering the type of adhesive sheet to be used, the productivity or performance of the desired laminate, and the manufacturing equipment or manufacturing cost of the laminate. It is an arbitrary process that can be suitably employed. For example, even in a mode in which a special adhesive strength raising step is not performed after a part of the removing step by appropriate selection of the adhesive sheet used for the production of the laminate, the adhesive strength of the adhesive sheet to the adherend exceeds 2 N/25 mm. A part of the removal process may be performed before, and a laminate having an adhesive strength of 5 N/25 mm or more of the adhesive sheet to the adherend may be prepared.

The adhesive piece contained in the laminate produced by the method disclosed herein includes a base layer and an adhesive layer, and is bonded to an adherend through the adhesive layer. In this way, in the obtained laminate, what the adhesive piece and the adherend are bonded by the adhesive, that is, the adhesive maintains the desired viscoelasticity, the flexibility, impact resistance, and stress of the laminate produced by the method disclosed herein It is preferable from the viewpoints of ease, low-temperature properties, adhesion between the adherend and the adhesive piece, and the like.

In the example shown in Fig. 2, the adherend 10 and the pressure-sensitive adhesive sheet 20 of substantially the same size are attached to cover the entire surface (overall area) on one side of the adherend 10, but the adherend ( The attaching mode of the adhesive sheet to 10) is not limited to this. For example, the adhesive sheet may be affixed so as to cover only a partial area on one side of the adherend, or a portion of the adhesive sheet may be affixed to protrude from the adherend. In addition, in the pressure-sensitive adhesive sheet used in the attaching step S10, the first region and the second region need only be connected to such an extent that these regions can be treated as a series of sheets. It is not disturbed that a cutting auxiliary structure such as a cut portion (such as a perforation line) or a half cut is provided at the boundary of the two regions. Here, the half cut refers to cutting of a depth that does not penetrate the pressure-sensitive adhesive sheet in the thickness direction, and is typically formed as cutting of a depth that does not penetrate the substrate layer in the thickness direction. Such indentation can be formed, for example, by entering a processing blade from the back surface of the substrate layer (opposite to the side on which the adhesive layer is laminated) to a depth not penetrating the substrate layer. In one aspect, from the viewpoint of improving the handleability of the adhesive sheet or reducing manufacturing cost, an adhesive sheet in which a cutting auxiliary structure is not provided at the boundary between the first region and the second region can be preferably used. In addition, the adhesive sheet used in the pasting step S10 may be provided with a mark to help the alignment of the adhesive sheet and the adherend. The indication may be a structural indication such as a through hole, a cutout, a recess, or a visual indication by optically detectable marking (for example, printing or coloring), or the arrangement of other members (for example, identification) It may be by attaching the label, fixing the element that enables signal transmission or reflection). Such a display may be provided on one or both of the first area and the second area, or may be provided on the boundary between the first area and the second area.

In the example shown in Fig. 4, in the cutting step S20, linear cutting is performed at a depth that penetrates the pressure-sensitive adhesive sheet and reaches the surface of the adherend, but the mode of cutting is not limited to this. For example, the first region and the second region after the cutting step S20 may be partially connected to the extent that a part of the removal step S30 can be appropriately performed. As an example of such a cutting process, a cutting process in which a perforation line or the like is discontinuous, a half-cut process, a combination of a perforation line and a half-cut (for example, a cut through a base layer and a depth of cut that does not penetrate the base layer) Cutting process of the aspect repeated alternately) etc. are mentioned. In addition, the said cutting process may be performed to the depth which penetrates an adhesive sheet to the surface of an adherend, and may be further penetrated through an adhesive sheet to reach some depth from the surface of an adherend, and does not penetrate the adhesive sheet. It may be done in depth (i.e., half cut). In the manufacturing method disclosed herein, when performing the partial removal step S30, the adhesive force of the pressure-sensitive adhesive sheet to the adherend is suppressed low, so that the first region and the second region are completely separated at least to a depth that penetrates the substrate layer. It is preferable to cut. This can be advantageous from the viewpoints of improving the pick-up property of the second region in some removal step S30, preventing the lift or misalignment of the first region, and improving the appearance accuracy of the first region.

In the example shown in FIG. 4, one end and the other end of the second region extending in a straight line reach the end of the pressure-sensitive adhesive sheet. It is preferable to set the second region so that at least one end of the second region reaches the end of the pressure-sensitive adhesive sheet, from the viewpoint of the pick-up property of the second region in the partial removal step S30. In an embodiment in which the second region does not reach the end of the adhesive sheet, the second region is picked up, for example, by attaching and pulling a strong adhesive tape to the back of the second region at one end of the second region. Can. Such a pickup method can also be employed in an aspect in which at least one end of the second region reaches the end of the adhesive sheet. In the method for manufacturing a laminate disclosed herein, the adhesive force of the pressure-sensitive adhesive sheet to the adherend at the time of the partial removal process is 2 N/25 mm or less, as described above, by a second method of attaching and pulling up the adhesive tape. It is advantageous from the viewpoint of improving the pickup property of the area.

In the aspect in which the second region is set to reach the end of the pressure-sensitive adhesive sheet, the width of the second region to the edge of the pressure-sensitive adhesive sheet is preferably 0.2 mm or more, and 0.5 mm or more from the viewpoint of pickup properties. It may be 1 mm or more. In order to improve the pick-up property, the second region may be configured to have a wider width in the vicinity of the second region reaching the end of the adhesive sheet. In addition, from the viewpoint of miniaturization of a product (electronic device, etc.) containing a laminate obtained by the manufacturing method disclosed herein, it is preferable that the width at which the second region reaches the edge of the adhesive sheet is 10 mm or less. , 8 mm or less is more preferable.

When the method of manufacturing a laminate disclosed herein includes an adhesive strength increasing step, the degree to which the adhesive strength is increased in the corresponding step is not particularly limited, and the adhesive strength after the corresponding step or the lamination obtained through the corresponding step compared to the adhesive force before the corresponding step It is only necessary that the sieve's adhesive strength is relatively high. In some embodiments, in the adhesion increasing step, the relationship between the adhesion A ₀ [N/25 mm] to the adherend before the step and the adhesion A ₁ [N/25 mm] to the adherend after the step is It is preferable to do so that the ratio (A ₁ /A ₀ )≥2 is satisfied. That is, in the step of increasing the adhesive strength, it is preferable to increase the adhesive strength of the pressure-sensitive adhesive sheet to the adherend to twice or more before the step. According to such a process for increasing the adhesive strength, there is a tendency that the ease of removal of the second region in the partial removal process and the strong adhesiveness of the pressure-sensitive adhesive piece to the adherend in the produced laminate tend to be compatible. In some embodiments, the ratio (A ₁ /A ₀ ) may be, for example, 3 or more, 5 or more, or 10 or more. The upper limit of the ratio (A ₁ /A ₀ ) is not particularly limited, but is preferably 10000 or less, 5000 or less, or 2000 or less from the viewpoint of suppressing the positional displacement or lifting of the first region before the adhesive strength increasing step. . Each of the adhesive strengths A ₀ and A ₁ was measured according to JIS Z0237 in the environment of 23° C., 50% RH, and the peel strength from the adherend of the adhesive sheet under the conditions of a peel angle of 180 degrees and a tensile speed of 300 mm/min. It can be grasped by measuring.

The adhesive force A ₀ of the adhesive sheet to the adherend before the adhesive strength increasing step may be, for example, approximately the same as the adhesive force A _P during the partial removal process. Therefore, each upper limit value and each lower limit value of the adhesive force A _P exemplified above can be independently applied to each of the upper and lower limit _values that the adhesive force A ₀ can take. In addition, each of the upper and lower limit values of the adhesive force A _P exemplified above can be applied to each of the upper and lower limit _values that the initial adhesive force B ₀ described later can independently take.

In the laminate produced by the method disclosed herein, the adhesive force A _F of the pressure-sensitive adhesive piece to the adherend may be, for example, 5N/25mm or more, 7N/25mm or more, 10N/25mm or more, and 12N It may be /25mm or more. A high adhesive force A _F is preferable from the viewpoint of suppressing peeling or lifting of the adhesive piece from the adherend when using the laminate. The upper limit of the adhesive force A _F is not particularly limited. From the viewpoint of facilitating compatibility with ease of peeling of the second region in some removal steps, in some embodiments, the adhesive force A _F may be, for example, 50 N/25 mm or less, or 40 N/25 mm or less, It may be 35 N/25 mm or less, or 30 N/25 mm or less.

Moreover, in the aspect which includes the process of increasing the adhesive force, the adhesive force A ₁ [N/25mm] to the adherend of the adhesive sheet after the adhesive force increasing step is, for example, an adherend of the adhesive piece in the produced laminate. It may be about the same as the adhesion to A _F. Therefore, each upper limit value and each lower limit value of the adhesive force A _F exemplified above can be independently applied to each of the upper and lower limit values that the adhesive force A ₁ can take. In addition, each of the upper and lower limit values of the adhesive force A _F exemplified above can be applied to each of the upper and lower limit values that the adhesive force B ₁ can take independently after stimulation, which will be described later.

Content of the stimulus to be applied to the pressure-sensitive adhesive sheet according to the adhesive force increases step is, for example, after stimulation of the initial adhesive strength B ₀ of the polyimide of the pressure-sensitive adhesive sheet using the adhesive strength increase ratio, which is defined as the ratio of the adhesive strength B ₁ (B ₁ / B ₀ ) may be set to meet a predetermined target value. The initial adhesive force B ₀ and the stimulus adhesive B ₁ are measured by the method described in Examples described later.

When the manufacturing method disclosed herein includes an adhesive strength increasing step, the adhesive strength increasing step is preferably performed such that the adhesive strength increasing ratio (B ₁ /B ₀ ) is, for example, 2 or more, and the adhesive strength increasing ratio (B ₁ It is more preferable that /B ₀ ) is 3 or more, 5 or more, 10 or more, or 15 or more. Also. From the viewpoint of reducing the load applied to the pressure-sensitive adhesive sheet and the adherend or improving the productivity of the laminate, the pressure-lifting step is performed so that the pressure-lifting ratio (B ₁ /B ₀ ) is approximately 10000 or less, 5000 or less, or 2000 or less. Can. In some embodiments, the adhesive strength increase ratio (B ₁ /B ₀ ) may be, for example, 1000 or less, 500 or less, 200 or less, or 100 or less.

Further, in flexible display panels, flexible printed wiring boards (FPCs), devices in which a display panel and a wiring board are integrated, flexible substrate materials are used, and from the viewpoint of heat resistance and dimensional stability, polyimide films are used as the substrate materials. There are many. The adhesive sheet showing the above-described adhesive strength B ₀ , B ₁ or adhesive strength increase ratio (B ₁ /B ₀ ) with respect to the polyimide is used in the production of the laminate in an aspect in which the polyimide is an adherend, and is partially removed in some removal steps. The peeling workability of the two regions is good, and when using the obtained laminate, it can exhibit the property of excellent adhesion reliability with the adherend. By using these properties, the film coverlay of the FPC can be formed with high precision and efficiency. Therefore, the method disclosed herein can be preferably applied, for example, to the production of FPCs with film coverlays.

The heating temperature in the case of heating as a stimulus imparted to the adhesive sheet in the adhesive strength increasing step is not particularly limited, and considering workability, economy, and heat resistance of the substrate layer or adherend that may be included in the adhesive sheet, etc. Can be set. The heating temperature may be less than 150°C, for example, 120°C or less, 100°C or less, 80°C or less, or 70°C or less. Moreover, the said heating temperature can be 40 degrees C or more, 50 degrees C or more, or 60 degrees C or more, for example, and may be 80 degrees C or more, and may be 100 degrees C or more. According to a higher heating temperature, the adhesive force can be increased by a shorter treatment time. The heating time is not particularly limited, for example, 1 hour or less, 30 minutes or less, 10 minutes or less, or 5 minutes or less. Alternatively, the heat treatment may be performed for a longer period of time (for example, 2 hours or longer, 5 hours or longer), to the extent that no significant thermal deterioration occurs in the adhesive sheet or adherend. In addition, heat processing may be performed at once, or it may be divided into multiple times.

The pressure-sensitive adhesive sheet used in the sticking process may include only one region (first region) that is an adhesive piece constituting the laminate in one pressure-sensitive adhesive sheet, and is spaced apart from each other, for example, as shown in FIG. 2. Two first regions may be included, or three or more first regions may be included. When one adhesive sheet contains a plurality of first regions, the shapes of those first regions may be the same or different. Similarly, the pressure-sensitive adhesive sheet used in the pasting step may include only one second region, which is peeled and removed in some removal steps, in one adhesive sheet, for example, as shown in FIG. 4, or two or more. Or you may include three or more. When one adhesive sheet contains a plurality of second regions, the shape of these second regions may be the same or different.

In the method for manufacturing a laminate according to several aspects, as the pressure-sensitive adhesive sheet and adherend used in the pasting step, one comprising a plurality of units corresponding to the laminate produced by the method can be used. Such an aspect is a process performed after the pasting step, and may further include a dividing step of dividing the adhesive sheet and the adherend into the unit. The said dividing process can be performed at arbitrary time after performing a pasting process. For example, by performing a division process at least after the cutting process is completed, a plurality of units can be combined to perform the cutting process. The manufacturing method disclosed herein can be implemented, for example, in an aspect in which the above-described dividing step is included between the (a) cut step and a part of the removing step. In the manufacturing method including an adhesive strength raising process after some removal processes, you may implement the said division process in the aspect included, for example, between (b) a partial removal process and an adhesive strength raising process, or (c) after an adhesive strength raising process. You may combine 1 or 2 or more of the aspect of said (a)-(c). Moreover, the said aspect (a) can be implemented preferably using the adhesive sheet provided with the adhesive layer 2 mentioned later, for example. The aspect (b) or the aspect (c) can be preferably carried out using, for example, an adhesive sheet provided with the adhesive layer 1 or the adhesive layer 2 described later.

<<Manufacturing device>>

The method for manufacturing a laminate disclosed herein is, for example, as shown in FIG. 5, the first mechanism of the affixing mechanism 51 for affixing the adhesive sheet 20 to the adherend 10 and the adhesive sheet 20 The cutting mechanism 52 which cuts the boundary between the region 21 and the second region 22 and the second region 22 are avoided while leaving the first region 21 on the adherend 10 It can implement using the laminated body manufacturing apparatus 50 provided with the peeling mechanism 53 which peels and removes from the complex 10.

The sticking mechanism 51 is configured to be able to perform the sticking process in any of the manufacturing methods disclosed herein, for example, adherend supply means, adhesive sheet supply means, pressure-sensitive adhesive sheet to adherend, etc. It may include one or two or more. The cutting mechanism 52 is configured to be able to carry out the cutting process in any of the manufacturing methods disclosed herein, and may include one or two or more of the cutting means as exemplified above. The peeling mechanism 53 is configured to be able to perform a part of the removal process in any of the methods disclosed herein, for example, one or two or more such as pickup means, holding means, peeling means, etc. in the second region It may include.

In addition, a laminate manufacturing apparatus that can be used in the implementation of a method for manufacturing a laminate of an aspect including an adhesive strength increasing step is, for example, a mechanism for imparting a stimulus to increase the adhesive strength to a first region, and not illustrated in the adhesive force It may further include a lifting mechanism. The adhesive force increasing mechanism is configured to provide a stimulus capable of increasing the adhesive force of the pressure-sensitive adhesive sheet with respect to the pressure-sensitive adhesive sheet so that the pressure-sensitive adhesive force increase step in any of the methods disclosed herein can be performed. The sticking mechanism may include, for example, one or two or more of UV irradiation means (UV irradiation lamp, mirror for light path adjustment, etc.), heating means (warm air heater, infrared heater, electric heater, etc.), press means, and the like.

Moreover, the manufacturing apparatus used for the manufacturing method of the laminated body of the aspect including a division process can further include a division mechanism not shown. The dividing mechanism can be configured to be capable of performing a dividing process using known dividing means such as cutting with a Thompson blade, pinnacle blade, rotating blade, knife, or laser cutting, water jet cutting, blade cutting, or the like.

<< adhesive sheet >>

Hereinafter, some examples of the pressure-sensitive adhesive sheet that can be preferably employed to implement the method for manufacturing a laminate disclosed herein are described, but are not intended to limit the scope of the present invention.

The method for manufacturing a laminate disclosed herein can be preferably carried out using a pressure-sensitive adhesive sheet comprising a substrate layer and a pressure-sensitive adhesive layer laminated on at least the adherend side of the substrate layer. According to the pressure-sensitive adhesive sheet having the pressure-sensitive adhesive layer laminated on the substrate layer, since the pressure-sensitive adhesive layer can be reinforced by the substrate layer, the second region is easily peeled from the adherend in some removal steps.

<base layer>

Various film substrates can be preferably used as the substrate layer. The film base material may be a porous base material such as a foam film or a non-woven fabric sheet, a non-porous base material, or a structure in which a porous layer and a non-porous layer are laminated. In some aspects, as the base material, those containing a resin film capable of independently maintaining shape (independent or independent) as a base film can be preferably used. Here, the term "resin film" means a resin film having a non-porous structure and typically containing substantially no bubbles (voidless). Therefore, the said resin film is a concept different from a foam film or a nonwoven fabric. The resin film may be of a single-layer structure or a multi-layer structure of two or more layers (for example, a three-layer structure).

Examples of the resin material constituting the resin film include polyamide (PA), polyimide (PI), polyamideimide (PAI), polyether, such as polyester, polyolefin, nylon 6, nylon 66, and partially aromatic polyamide. Etherketone (PEEK), polyethersulfone (PES), polyphenylene sulfide (PPS), polycarbonate (PC), polyurethane (PU), ethylene-vinyl acetate copolymer (EVA), polytetrafluoroethylene Fluorine resins such as (PTFE), acrylic resins, polyacrylates, polystyrene, polyvinyl chloride, and polyvinylidene chloride resins can be used.

The said resin film may be formed using the resin material containing 1 type of such resin alone, or may be formed using the resin material in which 2 or more types are blended. The resin film may be non-stretched or stretched (for example, uniaxial stretching or biaxial stretching). For example, polyethylene terephthalate (PET) film, polyethylene naphthalate (PEN) film, non-stretched polypropylene (CPP) film, biaxially stretched polypropylene (OPP) film, low density polyethylene (LDPE) film, linear low density polyethylene Resin films such as (LLDPE) films and PP/PE blend films can be preferably used. PET films, PEN films, PPS films, and PEEK films are examples of resin films in which strength and dimensional stability are preferred from the viewpoint. PET films and PPS films are particularly preferred from the viewpoint of availability and the like, and PET films are particularly preferred.

To the resin film, known additives such as light stabilizers, antioxidants, antistatic agents, colorants (dyes, pigments, etc.), fillers, slip agents, anti-blocking agents, etc. are required within a range that does not significantly interfere with the effects of the present invention. It can be blended according to.

The manufacturing method of a resin film is not specifically limited. For example, conventionally known conventional resin film molding methods, such as extrusion molding, inflation molding, T die-cast molding, and calender roll molding, can be suitably employed.

The base layer may be substantially constructed from such a base film. Alternatively, the base layer may include an auxiliary layer in addition to the base film. Examples of the auxiliary layer include an optical property adjustment layer (for example, a colored layer and an antireflection layer), a surface treatment layer such as a printed layer or a laminate layer, an antistatic layer, a primer layer, and a release layer for imparting a desired appearance to the base layer. Can be heard.

On the side of the substrate layer on which the pressure-sensitive adhesive layer is laminated, if necessary, corona discharge treatment, plasma treatment, ultraviolet irradiation treatment, acid treatment, alkali treatment, formation of a primer layer by application of a primer (primer), Conventionally known surface treatments may be performed. The surface treatment may be a treatment for improving the anchorability of the pressure-sensitive adhesive layer to the base layer. The composition of the primer used for forming the undercoat layer is not particularly limited, and can be appropriately selected from known ones. The thickness of the undercoat layer is not particularly limited, but usually about 0.01 µm to 1 µm is suitable, and about 0.1 µm to 1 µm is preferable. Other treatments that can be carried out on the base layer as necessary include antistatic layer forming treatment, colored layer forming treatment, and printing treatment. These treatments can be applied alone or in combination.

<<adhesive layer>>

The composition of the pressure-sensitive adhesive constituting the pressure-sensitive adhesive layer is not particularly limited. The pressure-sensitive adhesive exhibits rubber elasticity in the room temperature region, such as acrylic polymers, rubber-based polymers, polyester-based polymers, urethane-based polymers, polyether-based polymers, silicone-based polymers, polyamide-based polymers, and fluorine-based polymers, which are well known in the field of pressure-sensitive adhesives. One or two or more kinds of various polymers may be included as a base polymer (a main component in the polymer component, that is, a component occupying more than 50% by weight). Among them, acrylic pressure sensitive adhesives and rubber pressure sensitive adhesives are exemplified as preferred pressure sensitive adhesives. Here, the acrylic adhesive refers to an adhesive containing an acrylic polymer as a base polymer. The same applies to rubber-based adhesives. In addition, the said acrylic polymer means the polymer material in which 50 weight% or more of the whole monomer component which comprises the said acrylic polymer is an acrylic monomer. In addition, in this specification, an acrylic monomer means the monomer which has at least 1 (meth)acryloyl group in 1 molecule. In addition, the said (meth)acryloyl group is a meaning indicating comprehensively an acryloyl group and a methacryloyl group.

Some examples of the pressure-sensitive adhesive layer that can be preferably used in the production method disclosed herein include (1) an pressure-sensitive adhesive layer containing a base polymer and a siloxane structure-containing polymer (hereinafter also referred to as "adhesive layer (1)"), And (2) an adhesive layer (hereinafter also referred to as "adhesive layer (2)") formed of a photocurable composition comprising a base polymer and a photocuring agent. Hereinafter, the pressure-sensitive adhesive layer 1 and the pressure-sensitive adhesive layer 2 will be described in detail, but the pressure-sensitive adhesive sheet used in the production method disclosed herein is not limited to having these pressure-sensitive adhesive layers.

<Adhesive layer containing base polymer A and siloxane structure-containing polymer B>

The pressure-sensitive adhesive layer (1) contains a base polymer A and a polymer B containing a siloxane structure, and after bonding to an adherend, the adhesive strength is suppressed to be low for a while in a room temperature region (for example, 20°C to 30°C), It can exhibit the property of greatly increasing the adhesive strength by aging (which may be heating, aging, a combination of these, etc.). Therefore, it can be preferably used in the method for manufacturing a laminate disclosed herein. The pressure-sensitive adhesive layer 1 can be formed of a pressure-sensitive adhesive composition containing a base polymer A or a precursor thereof and a polymer B containing a siloxane structure. The shape of the pressure-sensitive adhesive composition is not particularly limited, and may be various forms such as, for example, a water dispersion type, a solvent type, a hot melt type, and an active light curing type (for example, UV curing type).

(Base polymer A)

As the base polymer A (hereinafter sometimes abbreviated as "polymer A") of the pressure-sensitive adhesive layer 1, an acrylic polymer can be preferably used. When an acrylic polymer is used as the polymer A, good compatibility with the polymer B tends to be easily obtained. The good compatibility between polymer A and polymer B is through the improvement of the mobility of polymer B in the pressure-sensitive adhesive layer, and the adhesive having low adhesiveness in some removal steps and strong adhesiveness after the adhesive strength increase treatment (for example, heat treatment) It is preferable because it can contribute to the realization of the layer (1). It is preferable that 50 weight% or more of the adhesive layer (1) is an acrylic polymer.

As the acrylic polymer, for example, those in which 40% by weight or more of the total amount of monomer components constituting the acrylic polymer is (meth)acrylic acid alkyl ester can be preferably used. As the (meth)acrylic acid alkyl ester, those having a straight or branched chain alkyl group having 1 to 20 carbon atoms (that is, C _1-20 ) at the ester end can be preferably used. Easy point balance of properties, the configuration of monomer components the total amount of (meth) acrylic acid C ₁ of the acrylic _polymer-20, proportion of the alkyl ester is, for example, may be a least 50% by weight, and even more than 55 wt%, 60 wt. % Or more. For the same reason, the configuration of the entire amount of monomer components of (meth) acrylic acid C _{1 - 20} alkyl ester, the ratio of, for example, and even less than 99.9% by weight, and less than 98% by weight, or may be 95 wt% or less. In some embodiments, the total amount of monomer components of the (meth) acrylic acid C _{1 - 20} proportion of the alkyl ester include, for example, and even less than 90% by weight, and even up to 85% by weight, is 80% or less by weight even.

(Meth) acrylic acid C _{1 - 20} Examples Non-limiting examples of the alkyl ester (meth) acrylate, methyl (meth) acrylate, ethyl (meth) acrylate, propyl (meth) acrylate, isopropyl (meth) acrylate, n- butyl, (Butyl) (meth)acrylate, (meth)acrylic acid s-butyl, (meth)acrylic acid t-butyl, (meth)acrylic acid pentyl, (meth)acrylic acid isopentyl, (meth)acrylic acid neopentyl, (meth)acrylic acid hexyl, ( Heptyl methacrylate, octyl (meth)acrylate, 2-ethylhexyl (meth)acrylate, isooctyl methacrylate, nonyl (meth)acrylate, isononyl methacrylate, decyl (meth)acrylate, (meth) Isodecyl acrylate, undecyl (meth)acrylate, dodecyl (meth)acrylate, tridecyl (meth)acrylate, isotridodecyl (meth)acrylate, tetradecyl (meth)acrylate, pentadecyl (meth)acrylate, (meth) ) Hexadecyl acrylate, heptadecyl (meth)acrylate, stearyl (meth)acrylate, isostearyl (meth)acrylate, nonadecyl (meth)acrylate, and ecosil (meth)acrylate.

Of these, at least (meth) acrylic acid C _{1 - 18} is preferable to use an alkyl ester, and at least (meth) acrylic acid C _{1 -} it is more preferable to use _14-alkyl ester. In some aspect, the configuration of monomer components of the acrylic polymer, (meth) acrylic acid C _{4 - 12} alkyl ester selected from a (preferably acrylic acid C _{4 - - 10} alkyl ester such as acrylic acid C _{6 10} alkyl ester) It may include at least one. For example, acrylic polymers containing one or both of n-butyl acrylate (BA) and 2-ethylhexyl acrylate (2EHA) are preferred, and acrylic polymers containing at least 2EHA are particularly preferred. Other (meth) which can be preferably used acrylic acid C _{1 - 18} Examples of the alkyl esters, methyl acrylate, methyl methacrylate (MMA), methacrylic acid n- butyl (BMA), 2-ethylhexyl methacrylate (2EHMA ), isostearyl acrylic acid (ISTA), and the like.

The constituent monomer component of the acrylic polymer may include (meth)acrylic acid alkyl ester as a main component, and other monomers (copolymerizable monomers) copolymerizable with (meth)acrylic acid alkyl ester, if necessary. As the copolymerizable monomer, a monomer having a polar group (eg, carboxyl group, hydroxy group, etc.) can be suitably used. The monomer having a polar group may be helpful in order to introduce a crosslinking point to the acrylic polymer or to increase the cohesive force of the acrylic polymer. A copolymerizable monomer can be used individually by 1 type or in combination of 2 or more type.

The following are mentioned as a non-limiting specific example of a copolymerizable monomer.

Carboxyl group-containing monomers: for example, acrylic acid, methacrylic acid, carboxyethyl acrylate, carboxypentyl acrylate, itaconic acid, maleic acid, fumaric acid, crotonic acid, isocrotonic acid, and the like.

Hydroxy group-containing monomers: for example, 2-hydroxyethyl (meth)acrylate, 2-hydroxypropyl (meth)acrylate, 3-hydroxypropyl (meth)acrylate, 4-hydroxybutyl (meth)acrylate, (meth) )6-hydroxyhexyl acrylate, 8-hydroxyoctyl (meth)acrylate, 10-hydroxydecyl (meth)acrylic acid, 12-hydroxylauryl (meth)acrylic acid, (4-hydroxymethylcyclohexyl)methyl ( (Meth)acrylic acid hydroxyalkyl, such as meth)acrylate; Monomers having a hydroxy group and an amide group, such as N-(2-hydroxyethyl)acrylamide (HEAA).

Nitrogen-containing monomers: for example, N-vinylpyrrolidone, methylvinylpyrrolidone, vinylpyridine, vinylpiperidone, vinylpyrimidine, vinylpiperazine, vinylpyrazine, vinylpyrrole, vinylimidazole, vinyloxazole , Vinyl morpholine, N-vinyl-3-morpholinone, N-vinyl-2-caprolactam, N-vinyl-1,3-oxazin-2-one, N-vinyl-3,5-morpholindione , N-acryloyl morpholine, N-vinyl carboxylic acid amides and the like.

In addition, cyano group-containing monomers, vinyl ester monomers, aromatic vinyl monomers, epoxy group-containing monomers, vinyl ether monomers, sulfo group-containing monomers, phosphoric acid group-containing monomers, acid anhydride group-containing monomers, and the like.

When using such a copolymerizable monomer, the amount of use is not particularly limited, but it is usually appropriate to make the total amount of the monomer component 0.01% by weight or more. From the viewpoint of better exhibiting the effect of using the copolymerizable monomer, the amount of the copolymerizable monomer may be 0.1% by weight or more of the total amount of the monomer components, or 1% by weight or more. The amount of the copolymerizable monomer used can be 50% by weight or less of the total amount of monomer components, and preferably 40% by weight or less. Thereby, the cohesion force of an adhesive can be prevented from becoming too high, and the tack feeling at normal temperature (25 degreeC) can be improved.

In some embodiments, it is preferable that the acrylic polymer contains at least one monomer selected from the group consisting of N-vinyl cyclic amide and hydroxyl group-containing monomers as its constituent monomer components.

By using the N-vinyl cyclic amide, the cohesive force or polarity of the pressure-sensitive adhesive can be adjusted, and the adhesive force after heating as a stimulus for increasing the adhesive force (hereinafter, also referred to as "adhesive force after heating") can be improved. As a specific example of N-vinyl cyclic amide, what has the corresponding structure among the nitrogen-containing monomers mentioned above is mentioned. Especially preferred are N-vinyl-2-pyrrolidone and N-vinyl-2-caprolactam. The amount of N-vinyl cyclic amide used is not particularly limited, but is usually set to 0.01% by weight or more (preferably 0.1% by weight or more, for example, 0.5% by weight or more) of the total amount of the constituent monomer components of the acrylic polymer. . In some embodiments, the amount of N-vinyl cyclic amide used may be 1% by weight or more of the total amount of the monomer components, 5% by weight or more, or 10% by weight or more. In addition, from the viewpoint of improving the tack feeling at room temperature (25°C) and improving flexibility at low temperatures, the amount of N-vinyl cyclic amide is usually set to 40% by weight or less of the total amount of the monomer components, and 30% by weight. % Or less, or 20% or less.

By using a hydroxyl group-containing monomer, the cohesive force and polarity of the pressure-sensitive adhesive can be adjusted, and the pressure-sensitive adhesive force can be improved after heating. In addition, the hydroxyl group-containing monomer provides a reaction point with a crosslinking agent (for example, an isocyanate-based crosslinking agent) described later, and the cohesive force of the pressure-sensitive adhesive can be increased by a crosslinking reaction. Suitable examples of the hydroxyl group-containing monomer include 2-hydroxyethyl acrylate (HEA), 4-hydroxybutyl acrylate (4HBA), and N-(2-hydroxyethyl)acrylamide (HEAA). The amount of the hydroxyl group-containing monomer is not particularly limited, but it is usually suitable to be 0.01% by weight or more (preferably 0.1% by weight or more, for example, 0.5% by weight or more) of the total amount of the constituent monomer components of the acrylic polymer. In some embodiments, the amount of the hydroxyl group-containing monomer used may be 1% by weight or more of the total amount of the monomer components, 5% by weight or more, or 10% by weight or more. In addition, from the viewpoint of improving the tack feeling at room temperature (25°C) or improving the flexibility at low temperatures, the amount of the hydroxyl group-containing monomer is usually set to 40% by weight or less of the total amount of the monomer components, and 30% by weight or less. It may be or may be 20% or less, or 10% or less or 5% or less.

In some embodiments, as a copolymerizable monomer, an N-vinyl cyclic amide and a hydroxyl group-containing monomer can be used in combination. In this case, the total amount of the N-vinyl cyclic amide and the hydroxyl group-containing monomer may be 0.1% by weight or more, 1% by weight or more, 5% by weight or more, and 10% by weight, for example, the total amount of the constituent monomer components of the acrylic polymer. % Or more, 15% or more, 20% or more, or 25% or more. Moreover, the total amount of the N-vinyl cyclic amide and the hydroxyl group-containing monomer can be, for example, 50% by weight or less of the total amount of the monomer components, and preferably 40% by weight or less.

The Tg of the polymer A is typically less than 0°C, preferably less than -10°C, more preferably less than -20°C. Since the pressure-sensitive adhesive containing the polymer A having a Tg of less than 0°C exhibits moderate fluidity (for example, the mobility of the polymer chain contained in the pressure-sensitive adhesive), it is easy to significantly increase the adhesive strength by performing heat treatment at an arbitrary timing. . In some embodiments, the Tg of the polymer A may be, for example, less than -30°C, less than -40°C, less than -50°C, or less than -60°C. The lower limit of the Tg of the polymer A is not particularly limited. From the viewpoint of ease of availability of the material and improvement of the cohesive force of the pressure-sensitive adhesive layer, a polymer A having a Tg of -80°C or higher can be suitably employed.

In this specification, the Tg of the polymer refers to the Tg obtained by the formula of Fox based on the nominal value described in the literature, catalog, or the like, or the composition of the monomer component used in the preparation of the polymer. The formula of Fox is a relational expression between the Tg of the copolymer and the glass transition temperature Tgi of the homopolymer obtained by polymerizing each of the monomers constituting the copolymer, as described below.

1/Tg=Σ(Wi/Tgi)

In the formula of Fox, Tg is the glass transition temperature of the copolymer (unit: K), Wi is the weight fraction of the monomer i in the copolymer (copolymerization ratio based on weight), Tgi is the homopolymer of the monomer i It shows the glass transition temperature (unit: K). When the polymer of the object related to the specification of Tg is a homo polymer, the Tg of the homo polymer and the polymer Tg of the object coincide.

As the glass transition temperature of the homopolymer used for the calculation of Tg, it is assumed that a value described in known data is used. Specifically, numerical values are exemplified in "Polymer Handbook" (3rd edition, John Wiley & Sons, Inc., 1989). For the monomers in which a plurality of types of values are described in the Polymer Handbook, the highest value is adopted.

Although not particularly limited, the weight average molecular weight (Mw) of the polymer A is usually about 50,000 or more, and from the viewpoint of obtaining a pressure-sensitive adhesive exhibiting better cohesiveness, for example, 100,000 or more, or 200,000 or more It may be, or may be 300,000 or more. Moreover, it is suitable that Mw of polymer A is usually about 5 million or less. The polymer A of such Mw is suitable for realizing an adhesive sheet having a high adhesive strength increase ratio, since it is easy to form an adhesive exhibiting moderate fluidity (mobility of polymer chains).

In this specification, the Mw of the polymer can be determined in terms of polystyrene by gel permeation chromatography (GPC). More specifically, Mw can be measured according to the method and conditions described in Examples described later.

The method for obtaining the acrylic polymer is not particularly limited, and various polymerization methods known as synthetic methods for acrylic polymers, such as solution polymerization, emulsion polymerization, bulk polymerization, suspension polymerization, and photopolymerization, can be suitably employed.

The initiator used for polymerization can be appropriately selected from conventionally known thermal initiators, photoinitiators, and the like, depending on the polymerization method. Non-limiting examples of the thermal initiator include azo-based initiators such as 2,2'-azobisisobutyronitrile (AIBN), persulfates such as potassium persulfate, peroxide-based initiators, and redox-based initiators. Non-limiting examples of the photoinitiator include benzoin ether photoinitiator, acetophenone photoinitiator, α-ketol photoinitiator, aromatic sulfonylchloride photoinitiator, photoactive oxime photoinitiator, benzoin photoinitiator, and benzyl photoinitiator And an initiator, a benzophenone-based photo initiator, a ketal-based photo initiator, a thioxanthone-based photo initiator, and an acylphosphine oxide-based photo initiator. An initiator can be used individually by 1 type or in combination of 2 or more type.

In some embodiments, a solution polymerization method can be preferably employed as a method for obtaining an acrylic polymer. As a solvent for solution polymerization, ethyl acetate, toluene, or the like is used. The solution concentration is usually about 20 to 80% by weight. As an initiator, various well-known things, such as azo type and peroxide type, can be used. In order to adjust the molecular weight, a chain transfer agent may be used. The reaction temperature is usually about 50 to 80°C, and the reaction time may be about 1 to 8 hours.

In some embodiments, the acrylic polymer is in the form of a partially polymerized product (acrylic polymer syrup) in which a portion of the monomer component is polymerized by irradiating ultraviolet (UV) light to a mixture of the monomer component and the initiator as described above. It may be included in the pressure-sensitive adhesive composition for forming the pressure-sensitive adhesive layer. The pressure-sensitive adhesive composition containing such an acrylic polymer syrup may be applied to a predetermined object to be coated, and UV irradiation may be used to complete polymerization. That is, the acrylic polymer syrup can be grasped as a precursor of the acrylic polymer. The pressure-sensitive adhesive layer 1 can be formed using, for example, an pressure-sensitive adhesive composition comprising such acrylic polymer syrup and polymer B.

(Polymer B containing siloxane structure)

The siloxane structure-containing polymer B (hereinafter sometimes abbreviated as “polymer B”) is a copolymer of a monomer having a polyorganosiloxane skeleton (hereinafter also referred to as “monomer S1”) and a (meth)acrylic monomer. The polymer B can function as a retardation agent for increasing the adhesion force, which contributes to suppression of the initial adhesion force and improvement of the adhesion rate increase ratio due to the low polarity and mobility of the polyorganosiloxane structure derived from the monomer S1. The monomer S1 is not particularly limited, and any monomer containing a polyorganosiloxane skeleton can be used. The monomer S1 promotes localization of the polymer B to the surface of the pressure-sensitive adhesive layer in the pressure-sensitive adhesive sheet before use (before adhesion to the adherend) due to the low polarity derived from the structure, and the light peeling property at the beginning of bonding (low adhesion) ). As the monomer S1, one having a polymerizable reactor at one end can be preferably used. According to the copolymerization of such monomer S1 and a (meth)acrylic monomer, polymer B having a polyorganosiloxane skeleton in a side chain is formed. The polymer B having such a structure is likely to have a low initial adhesive strength and a high adhesive strength increase ratio due to side chain mobility and mobility.

As a monomer S1, the compound represented by the following general formula (1) or (2) can be used, for example. More specifically, X-22-174ASX, X-22-2426, X-22-2475, KF-2012 etc. are mentioned as a single-ended reactive silicone oil made by Shin-Etsu Chemical Co., Ltd. Monomer S1 can be used individually by 1 type or in combination of 2 or more type.

Here, R ³ in the general formulas (1) and (2) is hydrogen or methyl, R ⁴ is a methyl group or a monovalent organic group, and m and n are integers of 0 or more.

The functional group equivalent of the monomer S1 is, for example, preferably 700 g/mol or more and less than 15000 g/mol, more preferably 800 g/mol or more and less than 10000 g/mol, even more preferably 850 g/mol or more and less than 6000 g/mol, more preferably 1500 g/mol. Particularly preferred is mol or more and less than 5000 g/mol. When the functional group equivalent of the monomer S1 is less than 700 g/mol, the initial adhesive strength may not be sufficiently suppressed. If the functional group equivalent of the monomer S1 is 15000 g/mol or more, an increase in adhesive strength may be insufficient. When the functional group equivalent of the monomer S1 is within the above range, compatibility (for example, compatibility with polymer A) or mobility in the pressure-sensitive adhesive layer can be easily adjusted to an appropriate range, and initial low adhesion and steel when using a laminate It becomes easy to realize the pressure-sensitive adhesive sheet that is compatible with high levels of adhesion.

Here, the "functional group equivalent" means the weight of the main skeleton (for example, polydimethylsiloxane) bound to one functional group. About the notation unit g/mol, it is converted into 1 mol of functional groups. The functional group equivalent of the monomer S1 can be calculated, for example, from the spectral intensity of ¹ H-NMR (proton NMR) based on nuclear magnetic resonance (NMR). Calculation of the monomer S1 of the functional group equivalent weight (g / mol) based on the spectral intensity of ¹ H-NMR is, if necessary, on the basis of the general structural analysis method that affects ¹ H-NMR spectrum analysis of Japanese Patent No. 5951153 discloses It can be carried out with reference to description of.

In addition, when two or more types of monomers with different functional group equivalents are used as the monomer S1, an arithmetic average value can be used as the functional group equivalent of the monomer S1. That is, the functional group equivalent of the monomer S1 consisting of n kinds of monomers having different functional group equivalents (monomer S1 ₁ , monomer S1 ₂ ...monomer S1 _n ) can be calculated by the following formula.

The amount of monomer S1 of the functional group equivalent weight (g / mol) = (functional group equivalent weight of the monomer S11 × monomer S1 ₁ + monomer S1 ₂ of the functional group equivalent weight × monomer S1 ₂ amount + a ... + monomer S1 _n of the functional group equivalent weight × monomer S1 _n Mixing amount)/(mixing amount of monomer S1 ₁ + mixing amount of monomer S1 ₂ +...+ mixing amount of monomer S1 _n )

The content of the monomer S1 may be, for example, 5% by weight or more with respect to the total monomer component for preparing the polymer B, and is preferably 10% by weight or more from the viewpoint of better exhibiting the effect as a retardation agent for increasing adhesion. , May be 15% by weight or more, or 20% by weight or more. In addition, from the viewpoint of polymerization reactivity and compatibility, the content of the monomer S1 is preferably 60% by weight or less, and may be 50% by weight or less, and 40% by weight or less with respect to the total monomer component for producing the polymer B. Or may be 30% by weight or less. When the content of the monomer S1 is less than 5% by weight, the initial adhesive force may not be sufficiently suppressed. When the content of the monomer S1 is more than 60% by weight, the increase in adhesive strength may become insufficient.

The monomer component used in the preparation of the polymer B includes (meth)acrylic monomers which are added to the monomer S1 and copolymerizable with the monomer S1. By copolymerizing one or two or more (meth)acrylic monomers and monomer S1, the mobility of polymer B in the pressure-sensitive adhesive layer can be suitably adjusted. Copolymerization of the monomer S1 and the (meth)acrylic monomer can also help to improve the compatibility of polymer B and polymer A (eg, acrylic polymer).

As a (meth)acrylic-type monomer, (meth)acrylic-acid alkylester is mentioned, for example. For example, as the (meth)acrylic acid alkyl ester that can be used when the polymer A is an acrylic polymer, one or two or more of the monomers exemplified above can be used as the copolymerization component of the polymer B. In some aspect, the polymer B is a (meth) acrylate, C _{4 - 12} alkyl esters (preferably (meth) acrylic acid C _{4 - 10} alkyl esters such as (meth) acrylic acid C _{6 - 10} alkyl ester) At least 1 type of can be contained as a monomer unit. In some other embodiments, the polymer B is methacrylic acid C _{1 - 18} alkyl ester (preferably methacrylic acid C _{1 - 14} alkyl esters such as methacrylic acid, C _{1 - 10} alkyl ester) of at least One type can be contained as a monomer unit. The monomer units constituting the polymer B may include, for example, one or two or more selected from MMA, BMA and 2EHMA.

As another example of the said (meth)acrylic-type monomer, (meth)acrylic acid ester which has an alicyclic hydrocarbon group is mentioned. For example, cyclopentyl (meth)acrylate, cyclohexyl (meth)acrylate, isobornyl (meth)acrylate, dicyclopentanyl (meth)acrylate, 1-adamantyl (meth)acrylate, etc. Can be used. In some embodiments, the polymer B may contain at least one selected from dicyclopentanyl methacrylate, isobornyl methacrylate, and cyclohexyl methacrylate as monomer units.

The amount of the (meth)acrylic acid alkyl ester and the (meth)acrylic acid ester having the alicyclic hydrocarbon group may be, for example, 10% by weight or more and 95% by weight or less with respect to all the monomer components for preparing the polymer B, 20 It may be less than or equal to 95% by weight, and may be less than or equal to 30% by weight, less than or equal to 90% by weight, less than or equal to 90% by weight, or less than or equal to 85% by weight, or greater than or equal to 50% by weight.

As another example of a monomer that may be included together with the monomer S1 as a monomer unit constituting the polymer B, as the monomer that can be used when the polymer A is an acrylic polymer, various copolymerizable monomers exemplified above can be mentioned.

In some embodiments, by including the monomer unit common to the monomer unit included in the polymer B in the polymer A, the mobility of the polymer B in the pressure-sensitive adhesive layer can be improved, and the adhesion strength increase ratio can be improved. It is effective that the common monomer unit is a component that accounts for 5% by weight or more of the total monomer units constituting the polymer B, and 10% by weight or more (more preferably 20% by weight or more, for example, 30% by weight or more) It is preferable that it is a component to occupy. The proportion of the common monomer units in the total monomer units constituting the polymer A may be, for example, 1% by weight or more, preferably 3% by weight or more, more preferably 5% by weight or more, and 7% by weight It may be above. When the ratio of the common monomer units to the total monomer units constituting the polymer A increases, the effect of improving the compatibility tends to be better exhibited. In addition, in consideration of the balance with other properties, the proportion of the common monomer units in the total monomer units constituting the polymer A may be 50% by weight or less, 30% by weight or less, or 15% by weight or less. As a non-limiting example of a monomer that can be preferably employed as a common monomer unit, MMA, BMA, 2EHMA, methyl acrylate (MA), BA, 2EHA, cyclohexyl (meth)acrylate, isobornyl (meth) Acrylate, dicyclopentanyl (meth)acrylate, and the like.

The Mw of the polymer B is not particularly limited. Mw of polymer B may be 1000 or more, for example, 5000 or more. From the viewpoint of improving the adhesive strength increase by heating, in some embodiments, the Mw of the polymer B may be, for example, 10000 or more, 12000 or more, 15000 or more, 15000 or more, or 20000 or more do. In addition, Mw of the polymer B may be, for example, 100000 or less, 70000 or less, 50000 or less, or less than 50000 from the viewpoint of easily peeling the second region from the adherend in some removal steps. It may be less than 40000, less than 35000, or less than 30000, or less than 28000, or less than 25000. When the Mw of the polymer B is within the range of any of the above-mentioned upper and lower limits, compatibility and mobility in the pressure-sensitive adhesive layer can be easily adjusted to a suitable range, and low adhesiveness in some removal processes and strong adhesiveness when using a laminate are high level. It becomes easy to be compatible with.

Polymer B can be produced, for example, by polymerizing the above-mentioned monomers by known methods such as solution polymerization, emulsion polymerization, bulk polymerization, suspension polymerization, and photopolymerization.

Chain transfer agents can be used to adjust the molecular weight of polymer B. Examples of the chain transfer agent used include compounds having a mercapto group, such as octyl mercaptan, lauryl mercaptan, t-nonyl mercaptan, t-dodecyl mercaptan, mercaptoethanol, and α-thioglycerol; Thioglycolic acid; Methyl thioglycolate, ethyl thioglycolate, propyl thioglycolate, butyl thioglycolate, t-butyl thioglycolate, 2-ethylhexyl thioglycolate, octyl thioglycolate, isooctyl thioglycolate, decyl thioglycolate Thioglycolic acid esters such as thioglycolic acid dodecyl, ethylene glycol thioglycolic acid ester, neopentyl glycol thioglycolic acid ester, and pentaerythritol thioglycolic acid ester; α-methylstyrene dimer; And the like.

The amount of the chain transfer agent is not particularly limited, but is usually 0.05 parts by weight to 20 parts by weight, preferably 0.1 parts by weight to 15 parts by weight, and more preferably 0.2 parts by weight to 10 parts by weight based on 100 parts by weight of the monomer. It is suitable. By adjusting the use amount of the chain transfer agent in this way, polymer B of a suitable molecular weight can be obtained. A chain transfer agent can be used individually by 1 type or in combination of 2 or more type.

Although not particularly limited, the amount of the polymer B used may be, for example, 0.1 part by weight or more with respect to 100 parts by weight of the amount of the polymer A, and may be 0.3 part by weight or more from the viewpoint of obtaining a higher effect, 0.4 It may be more than parts by weight, may be more than 0.5 parts by weight, or more than 1 part by weight or more than 2 parts by weight. In addition, from the viewpoint of avoiding excessive reduction in cohesion, the amount of polymer B used per 100 parts by weight of polymer A may be, for example, 75 parts by weight or less, 50 parts by weight or less, 20 parts by weight or less, and 10 parts by weight or less It may be less than or equal to 8 parts by weight, or less than or equal to 5 parts by weight.

The pressure-sensitive adhesive layer can contain polymers (arbitrary polymers) other than polymer A and polymer B as necessary within a range that does not significantly impair the effect obtained by the technology disclosed herein. The amount of the optional polymer used is usually 20% by weight or less of the total amount of the polymer components included in the pressure-sensitive adhesive layer. In some embodiments, the amount of the optional polymer used may be 5% by weight or less, or 1% by weight or less, of the entire polymer component. An adhesive layer substantially free of polymers other than polymer A and polymer B may be used.

(Crosslinking system)

A crosslinking agent may be used in the pressure-sensitive adhesive layer, if necessary, for the purpose of adjusting cohesion. As a crosslinking agent, a crosslinking agent known in the field of an adhesive can be used, and examples thereof include an isocyanate crosslinking agent, an epoxy crosslinking agent, an oxazoline crosslinking agent, an aziridine crosslinking agent, a carbodiimide crosslinking agent, and a metal chelate crosslinking agent. have. In particular, isocyanate-based crosslinking agents, epoxy-based crosslinking agents, and metal chelate-based crosslinking agents are preferred. A crosslinking agent can be used individually by 1 type or in combination of 2 or more type. The technique disclosed herein can be preferably carried out in an aspect in which at least an isocyanate-based crosslinking agent is used as the crosslinking agent.

Examples of the isocyanate-based crosslinking agent include lower aliphatic polyisocyanates such as butylene diisocyanate and hexamethylene diisocyanate; Alicyclic isocyanates such as cyclopentylene diisocyanate, cyclohexylene diisocyanate, and isophorone diisocyanate; Aromatic isocyanates such as 2,4-tolylene diisocyanate, 4,4'-diphenylmethane diisocyanate, and xylylene diisocyanate; Trimethylolpropane/tolylene diisocyanate trimer adduct (e.g., dosing agent ``Coronate L''), trimethylolpropane/hexamethylene diisocyanate trimer adduct (e.g., dosing agent ``Coronate HL'') , Trimethylolpropane adduct of xylylene diisocyanate (for example, "Takenate D110N" manufactured by Mitsui Chemicals, isocyanurate body of hexamethylene diisocyanate (for example, "Coronate HX" by Tosoh Corporation), etc. And isocyanate adducts.

Examples of the epoxy-based crosslinking agent include bisphenol A, epichlorohydrin-type epoxy resins, ethylene glycidyl ether, polyethylene glycol diglycidyl ether, glycerin diglycidyl ether, glycerin triglycidyl ether, and 1,6-hexanediol. Glycidyl ether, trimethylolpropane triglycidyl ether, diglycidyl aniline, diamine glycidylamine, N,N,N',N'-tetraglycidyl-m-xylylenediamine and 1,3 And bis(N,N-diglycidylaminomethyl)cyclohexane.

The amount used in the case of using a crosslinking agent is not particularly limited, and can be, for example, an amount exceeding 0 parts by weight based on 100 parts by weight of the polymer A. In some embodiments, the amount of the crosslinking agent used for 100 parts by weight of the polymer A may be, for example, 0.01 parts by weight or more, 0.05 parts by weight or more, 0.1 parts by weight or more, 0.5 parts by weight or more, 1 part by weight or more , 1.5 parts by weight or more, or 2 parts by weight or more. Higher cohesion tends to be obtained by increasing the amount of the crosslinking agent used. On the other hand, from the viewpoint of avoiding the reduction of the tag due to excessive cohesion improvement, the amount of the crosslinking agent used relative to 100 parts by weight of the polymer A is usually 15 parts by weight or less, and may be 10 parts by weight or less, or 5 parts by weight You may do as follows. If the amount of the crosslinking agent is not too large, it may be advantageous from the viewpoint of better expressing the effect of using the polymer B by using the fluidity of the pressure-sensitive adhesive.

In order to advance the crosslinking reaction more effectively, a crosslinking catalyst may be used. Examples of the cross-linking catalyst include metal-based cross-linking catalysts such as tetra-n-butyl titanate, tetraisopropyl titanate, ferrous iron, butyl tin oxide, and dioctyl tin dilaurate. Among them, tin-based crosslinking catalysts such as dioctyl tin dilaurate are preferred. The amount of the crosslinking catalyst is not particularly limited, and can be, for example, approximately 0.0001 parts by weight to 1 part by weight (typically 0.05 parts by weight or less) relative to 100 parts by weight of the polymer A.

In the pressure-sensitive adhesive layer, a polyfunctional monomer can be used as necessary. The polyfunctional monomer can be used for purposes such as adjustment of cohesive force by being used in place of the crosslinking agent as described above or in combination with the crosslinking agent. For example, in the pressure-sensitive adhesive layer formed of a photocurable pressure-sensitive adhesive composition, a polyfunctional monomer can be preferably used.

Examples of the polyfunctional monomer include ethylene glycol di(meth)acrylate, propylene glycol di(meth)acrylate, polyethylene glycol di(meth)acrylate, polypropylene glycol di(meth)acrylate, and neopentyl glycol di( Meth)acrylate, pentaerythritol di(meth)acrylate, pentaerythritol tri(meth)acrylate, dipentaerythritol hexa(meth)acrylate, ethylene glycol di(meth)acrylate, 1,6-hexane Diol di(meth)acrylate, 1,12-dodecanediol di(meth)acrylate, trimethylolpropane tri(meth)acrylate, tetramethylolmethanetri(meth)acrylate, allyl(meth)acrylate, vinyl (Meth)acrylate, divinylbenzene, epoxy acrylate, polyester acrylate, urethane acrylate, butyldiol (meth)acrylate, and hexyldiol di(meth)acrylate. Among them, trimethylolpropane tri(meth)acrylate, 1,6-hexanediol di(meth)acrylate, and dipentaerythritol hexa(meth)acrylate can be suitably used. A polyfunctional monomer can be used individually by 1 type or in combination of 2 or more type.

The amount of the polyfunctional monomer used varies depending on the molecular weight, the number of functional groups, and the like, but it is usually appropriate to be within the range of about 0.01 parts by weight to 3.0 parts by weight based on 100 parts by weight of the polymer A. In some embodiments, the amount of the polyfunctional monomer used may be, for example, 0.02 parts by weight or more, and 0.03 parts by weight or more, based on 100 parts by weight of Polymer A. Higher cohesion tends to be obtained by increasing the amount of the polyfunctional monomer used. On the other hand, from the viewpoint of avoiding the reduction of the tag due to excessive improvement in cohesion, the amount of the polyfunctional monomer may be 2.0 parts by weight or less, 100 parts by weight or less, or 0.5 parts by weight or less. The fact that the amount of the polyfunctional monomer is not too high may be advantageous from the viewpoint of better expressing the effect of using the polymer B by using the fluidity of the pressure-sensitive adhesive.

(Adhesive resin)

A tackifying resin can be included in an adhesive layer as needed. Although it does not specifically limit as tackifying resin, For example, rosin type tackifying resin, terpene type tackifying resin, phenol type tackifying resin, hydrocarbon type tackifying resin, ketone type tackifying resin, polyamide type tackifying resin, And epoxy-based tackifying resins and elastomeric tackifying resins. Tackifying resin can be used individually by 1 type or in combination of 2 or more type.

The content of the tackifying resin is not particularly limited, and can be set to exhibit appropriate adhesive performance depending on the purpose or use. The content of the tackifying resin with respect to 100 parts by weight of the polymer A (when two or more tackifying resins are included, the total amount thereof) can be, for example, about 5 to 500 parts by weight.

As the tackifying resin, one having a softening point (softening temperature) of approximately 80°C or higher (preferably approximately 100°C or higher, for example, approximately 120°C or higher) can be preferably used. According to the tackifying resin having a softening point equal to or more than the above-mentioned lower limit, there is a tendency that the initial low tackiness and the strong tackiness when using a laminate are effectively improved. The upper limit of the softening point is not particularly limited, and may be, for example, approximately 200° C. or less (typically 180° C. or less). The softening point of the tackifying resin can be measured based on the softening point test method (circular method) specified in JIS K2207.

(Formation of adhesive layer)

The pressure-sensitive adhesive layer 1 may be a cured layer of the pressure-sensitive adhesive composition. That is, the pressure-sensitive adhesive layer 1 can be formed by applying a pressure-sensitive adhesive composition such as a water-dispersion type, a solvent type, a photo-curable type, or a hot melt type to an appropriate surface, followed by appropriate curing treatment. When two or more types of curing treatments (drying, crosslinking, polymerization, cooling, etc.) are performed, they can be performed simultaneously or in multiple steps. In the pressure-sensitive adhesive composition using a partially polymerized monomer component (acrylic polymer syrup), a final copolymerization reaction is typically performed as the curing treatment. That is, a partial polymerization product is provided to a new copolymerization reaction to form a complete polymerization product. For example, if it is a photocurable adhesive composition, light irradiation is performed. If necessary, curing treatment such as crosslinking and drying may be performed. For example, when it is necessary to dry with a photocurable pressure-sensitive adhesive composition, photocuring may be performed after drying. In the pressure-sensitive adhesive composition using a fully polymerized product, typically, as the curing treatment, treatments such as drying (heat drying) and crosslinking are performed as necessary.

The application of the pressure-sensitive adhesive composition can be carried out using conventional coaters such as gravure roll coaters, reverse roll coaters, kiss roll coaters, dip roll coaters, bar coaters, knife coaters, spray coaters, and the like. The application of the pressure-sensitive adhesive composition and the other pressure-sensitive adhesive composition used for forming the pressure-sensitive adhesive layer 2 to be described later can be carried out in the same manner.

<Adhesive layer formed of photocurable composition containing base polymer P and photocuring agent>

The pressure-sensitive adhesive layer 2 contains a base polymer P and a photocuring agent, and exhibits a property of improving adhesion by curing by irradiation with actinic rays (for example, UV). By using such properties, for example, the adhesive force before photocuring is configured to be 2 N/25 mm or less, and after the photocuring, a sticking process, a cutting process, and a partial removal process are performed, and then photocuring to increase the adhesive force (typically Can be suitably used in the implementation of the method for producing a laminate disclosed herein in an aspect of raising to 5 N/25 mm or more. From the viewpoint of increasing the efficiency of curing by actinic light irradiation, it is preferable that the pressure-sensitive adhesive composition (photocurable composition) constituting the pressure-sensitive adhesive layer 2 contains a photoinitiator. From the viewpoint of suppressing the phenomenon that the pressure-sensitive adhesive remains on the adherend when the pressure-sensitive adhesive layer before photo-curing is peeled off and peeled off the pressure-sensitive adhesive sheet in the second region in some removal steps, that is, the base polymer P is It is preferable that a crosslinked structure is introduced.

(Base polymer P)

As the base polymer P (hereinafter sometimes abbreviated as "polymer P") of the pressure-sensitive adhesive layer 2, an acrylic polymer can be preferably used from the viewpoint of optical transparency and the like. For example, it is preferable that 50% by weight or more of the pressure-sensitive adhesive layer 2 is an acrylic polymer. As the acrylic polymer, those having 40 wt% or more of the total amount of the constituent monomer components are preferably the same (meth)acrylic acid alkyl esters as the polymer A described above.

It is preferable that an acrylic polymer contains the monomer component which has a crosslinkable functional group as a copolymerization component. Examples of the monomer having a crosslinkable functional group include a hydroxy group-containing monomer and a carboxyl group-containing monomer. As an example of a hydroxy group-containing monomer and a carboxyl group-containing monomer, the same thing as the monomer exemplified as the constituent monomer component of the polymer A contained in the pressure-sensitive adhesive layer 1 can be mentioned. Especially, it is preferable to contain a hydroxy group containing monomer. The hydroxyl group and carboxy group of the polymer P serve as a reaction point with a crosslinking agent described later. By introducing a crosslinked structure into the polymer P, the cohesive force is improved, the adhesiveness of the pressure-sensitive adhesive layer 2 is improved, and the fluidity of the pressure-sensitive adhesive is lowered, so the residual of the pressure-sensitive adhesive to the adherend in some removal steps tends to decrease. have.

In the acrylic polymer, the total amount of the hydroxy group-containing monomer and the carboxyl group-containing monomer relative to the total amount of the constituent monomer components is preferably 1 to 30% by weight, more preferably 3 to 25% by weight, and furthermore 5 to 20% by weight desirable. In particular, it is preferable that the content of the (meth)acrylic acid ester containing a hydroxy group is within the above range.

It is preferable that the acrylic polymer contains a nitrogen-containing monomer as a constituent monomer component. As an example of a nitrogen-containing monomer, the thing similar to the monomer illustrated as a structural monomer component of the polymer A contained in the adhesive layer 1 is mentioned. The content of the nitrogen-containing monomer relative to the total amount of the constituent monomer components is preferably 1 to 30% by weight, more preferably 3 to 25% by weight, and even more preferably 5 to 20% by weight. It is preferable that an acrylic polymer contains N-vinylpyrrolidone as a nitrogen-containing monomer in the said range.

When an acrylic polymer contains both a hydroxy group-containing monomer and a nitrogen-containing monomer as a monomer component, the cohesive force and transparency of the pressure-sensitive adhesive tend to increase. In the acrylic polymer, the total amount of the hydroxy group-containing monomer and the nitrogen-containing monomer relative to the total amount of constituent monomer components is preferably 5 to 50% by weight, more preferably 10 to 40% by weight, and even more preferably 15 to 35% by weight. Do.

Acrylic polymers include monomer components other than the above, such as cyano group-containing monomers, vinyl ester monomers, aromatic vinyl monomers, epoxy group-containing monomers, vinyl ether monomers, sulfo group-containing monomers, phosphoric acid group-containing monomers, acid anhydride group-containing monomers, and the like. You may include it.

In the acrylic polymer, the content of the monomer having a Tg of 40°C or higher of the homopolymer is preferably 5 to 50% by weight, and more preferably 10 to 40% by weight relative to the total amount of the constituent monomer components of the acrylic polymer. From the viewpoint of suppressing the adhesive residue in some removal processes, it is preferable that the Tg of the homopolymer contains a monomer component of 80°C or higher, and the Tg of the homopolymer includes a monomer component of 100°C or higher, from the viewpoint of suppressing the residual adhesive. It is more preferable to do. In the acrylic polymer, the content of the monomer having a Tg of 100°C or higher of the homopolymer relative to the total amount of the constituent monomer components is preferably 0.1% by weight or more, more preferably 0.5% by weight or more, and even more preferably 1% by weight or more , 3% by weight or more is particularly preferred. In particular, it is preferable that the content of MMA is within the above range. In addition, the suitable range of Tg of the acrylic polymer used as polymer P may be the same as the suitable Tg of polymer A mentioned above.

The acrylic polymer can be obtained by various known polymerization methods in the same manner as the polymer A contained in the pressure-sensitive adhesive layer 1. For example, a solution polymerization method can be preferably employed.

The adhesive strength of the pressure-sensitive adhesive layer before photocuring tends to depend on the component and molecular weight of the polymer P. From the viewpoint of achieving both suitable adhesion and suppression of adhesive residue in some removal processes, the weight average molecular weight of the acrylic polymer is preferably 100,000 to 5 million, more preferably 300 to 3 million, and more than 500,000 to 2 million. desirable. In addition, when a crosslinked structure is introduced into the polymer P, the molecular weight of the polymer P refers to the molecular weight before introducing the crosslinked structure.

(Crosslinking system)

From the viewpoint of providing a suitable cohesive force to the pressure-sensitive adhesive, it is preferable that a crosslinked structure is introduced into the polymer P. For example, a crosslinking structure is introduced by adding a crosslinking agent to the solution after polymer P is polymerized and heating it as necessary. As a crosslinking agent, an isocyanate type crosslinking agent, an epoxy type crosslinking agent, an oxazoline type crosslinking agent, an aziridine type crosslinking agent, a carbodiimide type crosslinking agent, a metal chelate type crosslinking agent, etc. are mentioned. These crosslinking agents react with functional groups such as hydroxyl groups introduced into the polymer P to form a crosslinking structure. As an isocyanate type crosslinking agent, the thing similar to the adhesive layer 1 can be used.

The amount of the crosslinking agent may be appropriately adjusted depending on the composition, molecular weight, and the like of the polymer P. The amount of the crosslinking agent to be used may be, for example, about 0.1 to 10 parts by weight, and preferably 0.3 to 7 parts by weight, more preferably 0.5 to 5 parts by weight, and even more preferably 1 to 4 parts by weight based on 100 parts by weight of the polymer P. Parts by weight. In order to promote the formation of a crosslinked structure, a crosslinking catalyst may be used in the same manner as the pressure-sensitive adhesive layer 1.

(Photocuring agent)

The pressure-sensitive adhesive composition constituting the pressure-sensitive adhesive layer 2 is configured to exhibit photocurability by adding to the polymer P and containing a photocuring agent. The pressure-sensitive adhesive layer 2 exhibits a property of improving the adhesive strength by photocuring by irradiating active light as a stimulus for increasing the adhesive strength after bonding with the adherend.

As the photocuring agent, a photocurable monomer or photocurable oligomer is used. As the photocuring agent, a compound having two or more ethylenically unsaturated bonds in one molecule is preferable. Moreover, the photocuring agent is preferably a compound showing compatibility with the polymer P. It is preferable that a photocuring agent is liquid at normal temperature from the point which shows suitable compatibility with polymer P. The photocuring agent is compatible with the polymer P and uniformly dispersed in the composition, whereby the contact area with the adherend can be secured, and the pressure-sensitive adhesive layer 2 with high transparency can be formed.

The compatibility of the polymer P and the photocuring agent is mainly affected by the structure of the compound. The structure and compatibility of the compound can be evaluated by, for example, Hansen solubility parameters, and the smaller the difference between the solubility parameters of the polymer P and the photocuring agent, the higher the tendency to increase compatibility.

From the viewpoint of high compatibility with acrylic polymers, it is preferable to use polyfunctional (meth)acrylates as photocuring agents. Examples of the polyfunctional (meth)acrylate include polyethylene glycol di(meth)acrylate, polypropylene glycol di(meth)acrylate, polytetramethylene glycol di(meth)acrylate, and bisphenol Aethylene oxide-modified di(meth)acrylic. Rate, bisphenol Apropylene oxide-modified di(meth)acrylate, alkanediol di(meth)acrylate, tricyclodecane dimethanol di(meth)acrylate, ethoxylated isocyanurate tri(meth)acrylate, penta Erythritol tri(meth)acrylate, pentaerythritol di(meth)acrylate, trimethylolpropane tri(meth)acrylate, ditrimethylolpropanetetra(meth)acrylate, ethoxylated pentaerythritoltetra(meth)acrylic Rate, pentaerythritol tetra(meth)acrylate, dipentaerythritol poly(meth)acrylate, dipentaerythritol hexa(meth)acrylate, neopentyl glycol di(meth)acrylate, glycerin di(meth)acrylic Rate, urethane (meth)acrylate, epoxy (meth)acrylate, butadiene (meth)acrylate, isoprene (meth)acrylate, and the like.

The compatibility of the polymer P and the photocuring agent also depends on the molecular weight of the compound. The smaller the molecular weight of the photocurable compound, the higher the compatibility with the polymer P tends to be. From the viewpoint of compatibility with the polymer P, the molecular weight of the photocuring agent is preferably 1500 or less, more preferably 1000 or less.

The type and content of the photocuring agent mainly affects the adhesive strength after photocuring. The smaller the functional group equivalent (i.e., the larger the number of functional groups per unit molecular weight), and the larger the content of the photocuring agent, the higher the adhesive strength after photocuring tends to be.

From the viewpoint of increasing the adhesive strength after photocuring, the functional group equivalent (g/eq) of the photocuring agent is preferably 500 or less, more preferably 450 or less. On the other hand, when the photocrosslinking density is excessively increased, the viscosity of the pressure-sensitive adhesive is lowered, and the adhesive force may be lowered. Therefore, the functional group equivalent of the photocuring agent is preferably 100 or more, more preferably 130 or more, still more preferably 150 or more, and particularly preferably 180 or more.

In the combination of an acrylic polymer and a polyfunctional acrylate photocuring agent, when the functional group equivalent of the photocuring agent is small, the interaction between the polymer P and the photocuring agent is strong, and the adhesive force before photocuring tends to be high. In the technique disclosed herein, it is preferable that the functional group equivalent of the photocuring agent is within the above range, even from the viewpoint of suppressing the adhesive force before photocuring to an appropriate range to increase the removal property of the second region in some removal steps.

The content of the photocuring agent in the pressure-sensitive adhesive composition is preferably 1 to 50 parts by weight, more preferably 5 to 40 parts by weight, and even more preferably 10 to 35 parts by weight relative to 100 parts by weight of the polymer P. When a photocurable compound is contained in an adhesive composition as an uncured (unreacted) monomer or oligomer, a photocurable adhesive layer is obtained. In order to include the photocuring agent in the composition in an uncured state, it is preferable to add the photocuring agent to the polymer solution after polymer P is polymerized.

When the content of the photocuring agent in the pressure-sensitive adhesive composition is increased, the photocuring agent is likely to bleed out to the surface of the pressure-sensitive adhesive layer. When the photocuring agent bleeds out in large quantities, the photocuring agent tends to remain in the adherend after removing the second region. On the other hand, by bleeding out a small amount of the photo-curing agent to the surface, it is possible to suppress the adhesive strength of the pressure-sensitive adhesive layer to the adherend, and to make it possible to properly achieve both low adhesion before photo-curing and strong adhesion after photo-curing.

(Photoinitiator)

It is preferable that the adhesive layer 2 contains a photoinitiator. The photoinitiator generates active species by irradiation with actinic rays, and accelerates the curing reaction of the photocuring agent. As the photoinitiator, a photocationic initiator (photoacid generator), photoradical initiator, photoanion initiator (photobase generator), or the like is used depending on the type of photocuring agent or the like. When a polyfunctional acrylate is used as the photocuring agent, it is preferable to use a photo radical initiator. Examples of the photo-radical initiators include hydroxy ketones, benzyl dimethyl ketals, amino ketones, acylphosphine oxides, benzophenones, and trichloromethyl group-containing triazine derivatives. The photo-radical generators may be used alone or in combination of two or more. The content of the photoinitiator in the pressure-sensitive adhesive layer is preferably 0.001 to 10 parts by weight, more preferably 0.01 to 5 parts by weight relative to 100 parts by weight of the total amount of the pressure-sensitive adhesive layer.

(Other additives)

In addition to each component of the above example, the pressure-sensitive adhesive layer, silane coupling agents, tackifiers, plasticizers, softeners, deterioration inhibitors, fillers, colorants, ultraviolet absorbers, antioxidants, surfactants, antistatic agents and other additives disclosed herein You may contain it in the range which does not significantly impair the effect obtained by technique.

(Formation of adhesive layer)

The pressure-sensitive adhesive layer 2 can be formed by, for example, applying a pressure-sensitive adhesive composition comprising a polymer P, a photocuring agent, and components other than those used as necessary, to a suitable surface, and then drying and removing the solvent as necessary. As a drying method, a suitable method can be adopted. The heating and drying temperature is preferably 40°C to 200°C, more preferably 50°C to 180°C, still more preferably 70°C to 170°C. The drying time is preferably 5 seconds to 20 minutes, more preferably 5 seconds to 15 minutes, and still more preferably 10 seconds to 10 minutes.

When the pressure-sensitive adhesive composition contains a crosslinking agent, it is preferable that the crosslinking proceeds by heating or aging simultaneously with drying of the solvent or after drying of the solvent. The heating temperature and the heating time are appropriately set depending on the type of the crosslinking agent to be used, and crosslinking is usually performed by heating for about 1 minute to 7 days in the range of 20°C to 160°C. The heating for drying and removing the solvent may also serve as heating for crosslinking. Even after the crosslinking structure is introduced into the polymer by the crosslinking agent, the photocuring agent remains unreacted. For this reason, a photocurable pressure-sensitive adhesive layer 2 is formed, comprising a polymer P having a crosslinked structure introduced therein and an unreacted photocuring agent.

(Friction)

The pressure-sensitive adhesive layer 2 before photocuring has a friction force at a frequency of 5 Hz measured by a tapping mode of a friction force microscope (FFM) from the viewpoint of easily suppressing the adhesion, and is 2 to 5 times the friction force at a frequency of 0.1 Hz. desirable. Moreover, when the ratio of the frictional force of the frequency of 0.1 Hz and 5 Hz of the pressure-sensitive adhesive layer 2 is in the range, the adhesive force after photocuring tends to be greatly increased compared to before photocuring.

In FFM, the force acting between the probe of the scanning probe microscope (SPM) and the sample surface is converted into the plate spring displacement (torsion amount) of the cantilever, and this displacement is detected electrically. The displacement amount is proportional to the differential voltage, and the friction force is proportional to the spring constant and displacement amount of the cantilever. Therefore, the friction force is proportional to the FFM differential voltage. The ratio of the friction force at a frequency of 5 Hz and the friction force at a frequency of 0.1 Hz is equivalent to the ratio of both FFM differential signals.

The frictional force by nano tribology tends to reflect the adhesiveness of the pressure-sensitive adhesive layer with the surface adherend, and a small frictional force means that the pressure-sensitive adhesive surface is close to a liquid phase and has a low tenacity. When the surface of the pressure-sensitive adhesive layer has a viscosity, the frictional force increases and the frequency dependence appears on the frictional force measured by FFM. The frictional force measured at a specific frequency tends to reflect the individual properties of the components of the pressure-sensitive adhesive composition, whereas the frequency dependence tends to more accurately reflect the properties of the surface. The smaller the frequency dependence of the frictional force, the smaller the viscosity and the stronger the properties of the liquid phase. The greater the frequency dependence of the frictional force, the greater the viscosity and the higher the adhesion to the adherend. For example, when the base polymer and the photocuring agent of the pressure-sensitive adhesive layer are not completely compatible, a liquid photocuring agent bleeds out to the surface, and an adhesion inhibiting layer (WBL) is formed at the adhesion interface with the adherend. Since the properties of the liquid phase become stronger, the frequency dependence of the frictional force and frictional force tends to be small.

By controlling the compatibility of the polymer P and the photo-curing agent in the pressure-sensitive adhesive layer 2, a small amount of the photo-curing agent may bleed out on the surface of the pressure-sensitive adhesive layer to form WBL. When WBL is properly formed, the properties of the surface (adhesive interface) change, and the frequency dependence of the frictional force and frictional force becomes small. Thereby, it becomes easy to suppress the adhesive force before photocuring, and peeling of the 2nd region in the case where some removal process is performed before this photocuring becomes easy.

When the friction force at a frequency of 5 Hz of the pressure-sensitive adhesive layer before photocuring is 5 times or less of the friction force at a frequency of 0.1 Hz, the pressure-sensitive adhesive layer before photocuring tends to be easily peeled off. From the viewpoint of avoiding the bleed-out of the photocuring agent, the friction force at a frequency of 5 Hz of the pressure-sensitive adhesive layer is preferably 2 times or more, more preferably 3 times or more, and even more preferably 3.5 times or more, at a frequency of 0.1 Hz.

From the viewpoint of achieving proper adhesion and peelability to the adherend, the FFM difference signal at a frequency of 5 Hz of the pressure-sensitive adhesive layer before photocuring measured using a cantilever with a spring constant of 40 N/m is preferably 0.01 to 1 V, and 0.05 It is more preferably from 0.9 to 0.9 V, more preferably from 0.1 to 0.8 V, and particularly preferably from 0.2 to 0.7 V.

From the viewpoint of increasing the adhesive strength after photocuring, the pressure-sensitive adhesive layer after photocuring preferably has a friction force at a frequency of 5 Hz measured by FFM of 5 times or more, and more preferably 5.5 times or more of a friction force at a frequency of 0.1 Hz. The FFM differential signal at a frequency of 5 Hz of the pressure-sensitive adhesive layer after photocuring measured using a cantilever having a spring constant of 40 N/m is preferably 0.1 V or more, more preferably 0.2 V or more, and even more preferably 0.3 V or more. From the viewpoint of improving the adhesion, the larger the frictional force of the pressure-sensitive adhesive layer after photo-curing, the more preferable. Therefore, although the upper limit of the frictional force is not particularly limited, the FFM differential signal at 5 Hz measured using a cantilever with a spring constant of 40 N/m is generally 10 V or less, and considering the characteristic balance of the adhesive, 5 V or less is preferable. Do.

The friction force at a frequency of 5 Hz of the pressure-sensitive adhesive layer after photocuring is preferably 1.5 times or more, more preferably 2 times or more, more preferably 2.5 times or more, and 3 times or more of a friction force at a frequency of 5 Hz of the pressure-sensitive adhesive layer before photocuring. The above is particularly preferable. The larger the ratio of the frictional force before and after photocuring, the higher the increase rate of the adhesive force due to photocuring tends to be. The friction force after photocuring is generally 20 times or less of the friction force before photocuring, and preferably 10 times or less.

In addition, in the FFM mode of the scanning probe microscope ("AFM5300E" manufactured by Hitachi High-Tech Science) of the frequency of 0.1 Hz and 5 Hz of the pressure-sensitive adhesive layer before and after photo-curing, the scan width in one direction is as follows. It is measured by performing a fractional measurement at 5 μm (10 μm scan in a round trip) and reading the differential voltage at a position of 3 μm from the left side of the measurement range.

(Measuring conditions)

Cantilever: ``Tap300E-G'' manufactured by BudgetSensors (equivalent to a spring constant of 40 N/m)

ADD value: 8.44V, DIF value: 0.4V, FFM value: 0V

Atmosphere: vacuum, room temperature

Scan rate: 0.1Hz, 1Hz and 5Hz

Examples of the active light rays that can be used for photocuring the pressure-sensitive adhesive layer 2 include ultraviolet (UV) light, visible light, infrared light, X-rays, α-rays, β-rays, and γ-rays. UV is preferable as the actinic ray from the viewpoint of easy suppression of curing of the pressure-sensitive adhesive layer in the storage state and easy curing. The irradiation intensity and irradiation time of the active light may be appropriately set depending on the composition, thickness, or the like of the pressure-sensitive adhesive layer.

The pressure-sensitive adhesive layer 2 is photocurable, and the timing at which the adhesive strength is increased by curing can be arbitrarily set. Therefore, after the adhesive sheet is attached to the adherend, it is possible to flexibly cope with the lead time of the manufacturing process of the device, since a part of the removal process can be performed at any timing between the time until the adhesive is photocured.

<Structure of adhesive sheet>

The thickness of the pressure-sensitive adhesive sheet used in the production method disclosed herein is not particularly limited, and may be, for example, about 3 μm to 11 mm. From the viewpoint of handling properties of the pressure-sensitive adhesive sheet, the thickness of the pressure-sensitive adhesive sheet is usually 5 μm or more, and may be 10 μm or more, or 30 μm or more. From the standpoint of peeling workability of the second region in some removal steps, etc., in some embodiments, an adhesive sheet having a thickness of 50 µm or more, 70 µm or more, or 90 µm or more can be preferably used. The thickness of the pressure-sensitive adhesive sheet may be, for example, 1000 µm or less, 600 µm or less, and 350 µm or less from the viewpoints of cutting processability in the cutting step and peeling workability of the second region in a partial removal step. It may be filtered, 200 µm or less, or 150 µm or less.

In the pressure-sensitive adhesive sheet comprising the base layer and the pressure-sensitive adhesive layer, the thickness of the pressure-sensitive adhesive layer is not particularly limited, and can be, for example, in a range of about 1 μm to 1000 μm. In some embodiments, the thickness of the pressure-sensitive adhesive layer may be, for example, 3 µm or more, 5 µm or more, 8 µm or more, 10 µm or more, 13 µm or more, 20 µm or more, or It may be more than 20 μm. By increasing the thickness of the pressure-sensitive adhesive layer, there is a tendency to obtain a laminate in which the pressure-sensitive adhesive piece is more firmly bonded to the adherend. On the other hand, if the thickness of the pressure-sensitive adhesive layer is excessively large, workability in some removal processes (eg, separation between the first and second regions) is caused by blocking of the pressure-sensitive adhesive in the first region and the pressure-sensitive adhesive in the second region. This may tend to degrade. From this viewpoint, the thickness of the pressure-sensitive adhesive layer may be, for example, 300 μm or less, 200 μm or less, 150 μm or less, 100 μm or less, 70 μm or less, or 50 μm or less, and 40 It may be less than or equal to µm, or less than or equal to 30 µm.

In the pressure-sensitive adhesive sheet comprising a base layer and an adhesive layer, the thickness of the base layer is not particularly limited, and may be, for example, about 2 μm to 10 mm. From the viewpoint of the handleability of the pressure-sensitive adhesive sheet and prevention of breakage of the second region in some removal steps, in some embodiments, the thickness of the substrate layer may be, for example, 5 μm or more, or 10 μm or more, and 25 It may be more than µm, may be 35 µm or more, 50 µm or more, or 60 µm or more. In addition, from the viewpoint of cutting processability in the cutting process, in some embodiments, the thickness of the base layer may be, for example, 1000 μm or less, 500 μm or less, 300 μm or less, or 200 μm or less. It may be filtered, 150 µm or less, 100 µm or less, or 90 µm or less.

The pressure-sensitive adhesive sheet used in the production method disclosed herein can be suitably implemented in an aspect in which the thickness Ts of the base layer is greater than the thickness Ta of the pressure-sensitive adhesive layer. That is, it is preferable that Ts/Ta is larger than 1. Although not particularly limited, Ts/Ta may be, for example, 1.1 or more, 1.2 or more, 1.5 or more, 2 or more, or 2.5 or more. In addition, Ts/Ta may be 50 or less, for example 20 or less, 10 or less, or 7 or less. By using the pressure-sensitive adhesive sheet having a structure that satisfies any of the above-mentioned upper limit values and/or satisfies any of the above-mentioned lower limit values, it is possible to achieve good peelability in some removal steps and adherends of the pressure-sensitive adhesive pieces in the finally obtained laminate. There is a tendency to achieve a good balance of solid adhesion to.

In some embodiments, the pressure-sensitive adhesive sheet used in the sticking process may have, for example, an area of 2500 cm 2 or more, and a short side having a length of 50 cm or more. In the aspect of using such a large-sized adhesive sheet, it is particularly meaningful to employ the manufacturing method disclosed herein. By using such an adhesive sheet, there is a tendency that, for example, effects of one or two or more of improvement of positional accuracy, improvement of shape accuracy, improvement of productivity, and the like are suitably exhibited. In addition, according to the manufacturing method disclosed herein, since the adhesive force to the adherend of the pressure-sensitive adhesive sheet exceeds 2N/25mm, a partial removal process of peeling and removing the second region of the pressure-sensitive adhesive sheet is performed, so that the wide surface as described above is used. Even the pressure-sensitive adhesive sheet is easy to remove and remove from the second region. According to the aspect in which the area of the adhesive sheet is 3600 cm 2 or more, more preferably 4900 cm 2 or more, or the short side has a length of 60 cm or more, more preferably 70 cm or more, a higher effect can be exhibited.

<Use>

According to the method disclosed herein, a laminate formed of a pattern with an adhesive piece on a adherend with high precision and excellent durability of the pattern can be efficiently produced. Taking advantage of these features, the methods disclosed herein include building materials such as exterior and interior materials for vehicles, building materials such as exterior and interior materials for buildings, window glass, signboards, signs, home appliances, optical products, and electronic products, or components thereof. As an adherend, such an adherend can be preferably applied to the application for producing a laminate partially covered by a pattern of adhesive pieces. The laminate may be the above-described various products or constituent members thereof. The adhesive piece is included in various products as a component of the laminate, so that the adherend contained in the laminate or the product or the member containing the laminate is decorated, marked, protected, reinforced, and shock absorbed. It may be helpful to impart functions such as relaxation of stress concentration, shape retention, and shape recovery. The method disclosed herein can be preferably applied, for example, to the production of FPCs with film coverlays.

In addition, in the optical member used in the optical product or in the electronic member used in the electronic product, a high degree of integration, small size, light weight, and thinning are in progress, and a plurality of thin optical members/electronic members having different linear expansion coefficients and thicknesses are stacked. Can. By using such a member as an adherend and forming a laminate in which the member is partially covered with an adhesive piece using the method disclosed herein, appropriate rigidity can be imparted to the optical member/electronic member. Thereby, in a manufacturing process and/or a product after manufacture, curl and curvature caused by the stress which may arise between a plurality of different members of the said linear expansion coefficient or thickness can be suppressed.

Further, in the manufacturing process of the optical product/electronic product, in the aspect of performing shape processing such as cutting processing on the thin optical member/electronic member as described above, the member (adhered body) is partially covered with an adhesive piece. By forming the laminate, the adhesive piece is used as a reinforcing member, alleviating local stress concentration to the optical member/electronic member accompanying processing of the laminate, and risks of cracking, cracking, peeling of the laminated member, and the like. Can be reduced. Handling by attaching a reinforcing member to the optical member/electronic member also helps to relieve local stress concentration during transport, lamination, rotation, etc. of the member, and to suppress bending and curvature due to the weight of the member. Can be

Further, devices such as an optical product or an electronic product including a laminate in which an adherend is partially covered with a pattern of the adhesive piece, in a step used for consumers in the market, when the device falls, when placed under a heavy object , Even when an unintentional stress is applied, such as when a flying object collides, the stress applied to the device can be relieved and the durability can be improved by the adhesive piece included in the device functioning as a reinforcing member.

The method disclosed herein can be preferably used, for example, to make a laminated body in which the constituent members of various portable devices (portable devices) are adhered, and the members are partially covered with a pattern of adhesive pieces. Here, the term "portable" means that it is not enough to simply carry it, and that the individual (standard adult) has a level of portability that can be carried relatively easily. In addition, examples of the mobile devices referred to herein include mobile phones, smartphones, tablet-type personal computers, notebook computers, various wearable devices, digital cameras, digital video cameras, sound devices (Walkman, IC recorders, etc.), calculators (electronic calculators, etc.) ), portable game devices, electronic dictionaries, electronic notebooks, electronic books, in-vehicle information devices, portable radios, portable TVs, portable printers, portable scanners, portable modems, etc., as well as mechanical wrist watches or pocket watches, Flashlights, hand mirrors, etc. may be included. Examples of members constituting the portable electronic device may include an optical film or display panel used in an image display device such as a thin-layer display such as a liquid crystal display or a film-type display. The method disclosed herein can be preferably applied also to applications in which various members in automobiles, home appliances, and the like are adhered and the member is partially covered with a pattern of an adhesive piece.

Example

Hereinafter, several examples according to the present invention will be described, but it is not intended to limit the present invention to those shown in these specific examples. In addition, "part" and "%" in the following description are a basis of weight unless there is particular notice.

(Preparation of polymer A1)

In a reaction vessel equipped with a stirring blade, a thermometer, a nitrogen gas introduction tube, and a cooler, 63 parts of 2-ethylhexyl acrylate (2EHA), 15 parts of N-vinylpyrrolidone (NVP), and methyl methacrylate (MMA) 9 Part, 13 parts of 2-hydroxyethyl acrylate (HEA) and 200 parts of ethyl acetate as a polymerization solvent were added, stirred at 60°C for 2 hours under a nitrogen atmosphere, and 0.2 parts of AIBN as a thermal initiator was added, and 6 parts at 60°C. Time reaction was carried out to obtain a solution of polymer A1. Mw of this polymer A1 was 1.1 million.

(Preparation of polymer A2)

A solution of polymer A2 was obtained by performing solution polymerization in the same manner as in the synthesis of polymer A1, except that the composition of the monomer used was changed to 2EHA/HEA=95/5 (weight ratio). Mw of this polymer A2 was 900,000.

(Preparation of polymer B1)

In a reaction vessel equipped with a stirring blade, a thermometer, a nitrogen gas introduction tube and a cooler, 40 parts of MMA, 20 parts of n-butyl methacrylate (BMA), 20 parts of 2-ethylhexyl methacrylate (2EHMA), functional group equivalent 900 g/mol polyorganosiloxane backbone-containing methacrylate monomer (trade name: X-22-174ASX, manufactured by Shin-Etsu Chemical Co., Ltd.) 9 parts, functional group equivalent of 4600 g/mol polyorganosiloxane backbone 11 parts of methacrylate monomer (trade name: KF-2012, manufactured by Shin-Etsu Chemical Co., Ltd.), 100 parts of ethyl acetate and 0.6 parts of thioglycerol as a chain transfer agent, and stirred at 70° C. under a nitrogen atmosphere for 1 hour. Then, 0.2 parts of AIBN was added as a thermal initiator, and after reacting at 70° C. for 3 hours, 0.1 parts by weight of AIBN was further added, and reaction was continued at 80° C. for 5 hours. In this way, a solution of polymer B1 containing a siloxane structure was obtained. Mw of this polymer B1 was 20000.

In addition, the weight average molecular weight of each polymer mentioned above was measured on condition of the following using GPC apparatus (made by Tosoh Corporation, HLC-8220GPC), and was calculated|required by polystyrene conversion.

Sample concentration: 0.2 wt% (tetrahydrofuran (THF) solution)

Sample injection volume: 10 μl

Eluent: THF, flow rate: 0.6 ml/min

·Measurement temperature: 40℃

·column:

Sample column; TSKguardcolumn SuperHZ-H (1 pc.)+TSKgel SuperHZM-H (2 pcs.)

Reference column; TSKgel SuperH-RC (1 pc.)

Detector: Differential Refractometer (RI)

<Production of the adhesive sheet>

(Adhesive sheet D1)

To the solution of the polymer A1, polymer A1 contained in the solution, per 100 parts, based on solid content, 2.5 parts of polymer B1, isocyanate-based crosslinking agent (trade name: Takenate D110N, trimethylolpropanexylylenediisocyanate, Mitsui Chemicals) ) 2.5 parts, and uniformly mixed to prepare an adhesive composition C1.

A pressure-sensitive adhesive composition C1 was directly applied to one surface of a 75 µm-thick PET film ("Lumirror S10" manufactured by Toray) that was not surface-treated, and heated and dried at 110°C for 2 minutes to form a pressure-sensitive adhesive layer having a thickness of 25 µm. , A release liner (MRQ50T100 manufactured by Mitsubishi Chemical, polyester film treated on one side with a silicone-based release agent, 50 µm thick) was bonded to the surface (adhesive surface) of the pressure-sensitive adhesive layer to protect it. In this way, the pressure-sensitive adhesive sheet D1 having a pressure-sensitive adhesive layer on one side of the base layer made of a PET film having a thickness of 75 µm and the surface of the pressure-sensitive adhesive layer (adhesive surface) protected with a release liner was obtained.

(Adhesive sheet D2)

To the solution of the polymer A1, per 100 parts of the polymer A1 contained in the solution, based on solid content, an isocyanate-based crosslinking agent (trade name: Takenate D110N, trimethylolpropanexylylenediisocyanate, manufactured by Mitsui Chemicals) 2.5 parts, spectacle 30 parts of the agent (trade name: A-200, polyethylene glycol #200 diacrylate, functional group equivalent of 154 g/eq, Shinnakamura Chemical Co., Ltd.) and 0.1 part of photoinitiator were added, and uniformly mixed to prepare adhesive composition C2. It was prepared. As the photoinitiator, 1-hydroxycyclohexylphenylketone ("Irgacure 184" manufactured by BASF) was used.

The pressure-sensitive adhesive composition C2 was directly applied to one side of a 75 µm-thick PET film (“Lumirror S10” manufactured by Toray) that was not surface-treated, and heated at 130° C. for 1 minute to dry. A µm pressure-sensitive adhesive layer was formed. The surface of the pressure-sensitive adhesive layer (adhesive surface) is protected by bonding a release liner (a PET film whose surface has been treated with a silicone releaser, a thickness of 25 µm) and protected, and crosslinked by performing an aging treatment for 4 days in an atmosphere of 25°C. Proceeded. In this way, an adhesive sheet D2 in a form in which the adhesive surface was protected with a release liner was obtained.

(Adhesive sheet D3)

To the solution of the polymer A2, per 100 parts of the polymer A2 contained in the solution, an isocyanate-based crosslinking agent (trade name: Takenate D110N, trimethylolpropanexylylenediisocyanate, manufactured by Mitsui Chemicals Co., Ltd.) was added 2.5 parts based on solid content, The adhesive composition C3 was prepared by mixing uniformly. A pressure-sensitive adhesive sheet D3 in a form in which the pressure-sensitive adhesive surface was protected with a release liner was obtained in the same manner as in the manufacture of the pressure-sensitive adhesive sheet D1, except that the pressure-sensitive adhesive composition C3 was used instead of the pressure-sensitive adhesive composition C1.

(Adhesive sheet D4)

The pressure-sensitive adhesive composition C4 was prepared in the same manner as in the preparation of the pressure-sensitive adhesive composition C1 except that the polymer B1 was not used. A pressure-sensitive adhesive sheet D4 in a form in which the pressure-sensitive adhesive surface was protected with a release liner was obtained in the same manner as in the production of the pressure-sensitive adhesive sheet D1, except that the pressure-sensitive adhesive composition C4 was used instead of the pressure-sensitive adhesive composition C1.

<Measurement of adhesion to polyimide>

A test piece for measuring adhesive strength was produced by fixing a polyimide film having a thickness of 12.5 µm ("Katon 50EN" manufactured by Toray DuPont) to a glass plate through a double-sided adhesive tape ("No.531" manufactured by Nitto Denko). Further, the adhesive sheets D1 to D4 were cut into a rectangle having a width of 25 mm to prepare samples for measurement.

Under the standard environment of 23° C. and 50% RH, the pressure-sensitive adhesive surface of the sample for measurement was pressed on the test piece by reciprocating a 2 kg roller. After leaving it for 30 minutes under the above-mentioned standard environment, using a tensile tester ("TCM-1kNB" manufactured by Mine Bea Co., Ltd.), peel strength (initial adhesive strength) under conditions of a peel angle of 180 degrees and a tensile speed of 300 mm/min according to JIS Z0237. ) B ₀ [N/25 mm] was measured.

In addition, in the measurement of the initial adhesive force B ₀ , the time for placing the sample for measurement on the test piece and then leaving it under the standard environment was changed to 12 hours and 24 hours. Other points were the same as the measurement of the initial adhesive strength B ₀ , and the adhesive strength [N/25mm] after 12 hours at room temperature and the adhesive strength [N/25mm] after 24 hours at room temperature were measured.

In addition, the measurement sample was pressed into the test piece in the same manner as the initial adhesive strength B ₀ measurement, and kept under fluorescent light at room temperature (here, about 25° C.) for about 4 weeks, and then peeled in the same manner as the initial adhesive strength B ₀ measurement. The strength (adhesive strength after 4 weeks) [N/25mm] was measured.

In addition, the measurement sample prepared from the adhesive sheet D1 was pressed into the test piece in the same manner as the measurement of the initial adhesive force B ₀ , left under the standard environment for 30 minutes, and then heated at 80° C. for 5 minutes. In addition, after leaving for 30 minutes under the above standard environment, the peel strength (adhesive strength after heating) [N/25mm] was measured under the conditions of a peel angle of 180 degrees and a tensile speed of 300 mm/min. It was 13.94 N/25 mm.

In addition, the measurement sample prepared from the adhesive sheet D2 was compressed into a test piece in the same manner as the measurement of the initial adhesive force B ₀ , left for 30 minutes under the above standard environment, and then used by UniField, manufactured by Ushio Corporation, for a wavelength of about The 365 nm ultraviolet light was irradiated to a light amount of 2000 mJ/cm 2. In addition, after leaving for 30 minutes under the above standard environment, the peel strength (adhesive strength after UV irradiation) [N/25mm] was measured under the conditions of a peel angle of 180 degrees and a tensile speed of 300 mm/min. It was 19.84 N/25 mm.

<Production of laminates>

(Production Example 1)

The adhesive sheet D1 was cut to a size of 25 mm in width and 100 mm in length to prepare an adhesive sheet for producing a laminate. In addition, as an adherend, a polyimide film having a thickness of 12.5 µm, a width of 30 mm, and a length of 120 mm (manufactured by Toray and DuPont, "Kapton 50EN") was prepared.

The center of the adherend and the center of the pressure-sensitive adhesive sheet were aligned, and the pressure-sensitive adhesive sheet was attached to the adherend by a hand roller (attachment process).

After attaching the pressure-sensitive adhesive sheet to the adherend, and before the following partial removal process, a cut process was performed. In the center of the width of the pressure-sensitive adhesive sheet in the obtained pressure-sensitive adhesive sheet/adhesive laminate, a second region having a width of 2 mm and a length of 100 mm extending linearly from one end to the other end in the long side direction of the pressure-sensitive adhesive sheet is set, and the second step is applied. Cutting was performed to cut only the adhesive sheet D1 by irradiating a laser on the adhesive sheet surface side along the boundary (two straight lines) of the region and the first area on both sides thereof. The said cutting process was performed on condition of the following using the laser cutting device "Spirit, Model number SI-30V" manufactured by GCC.

Speed: 9.0%

Power: 10.0%

DPI: 500

PPI: 400

About 12 hours after the adhesive sheet was affixed to the adherend, some removal steps were performed. Specifically, a slit shape having a width of 2 mm is obtained by peeling one end of the second region from the adherend and gripping it with a chuck of a tensile testing machine, and pulling it in the longitudinal direction of the pressure-sensitive adhesive sheet under conditions of a peeling angle of 180 degrees and a tensile speed of 300 mm/min. The second region of was peeled off from the adherend.

Subsequently, by performing the above-described heating (80° C., 5 minutes) as a stimulus for increasing the adhesive strength (adhesive strength increasing step), a target laminate, that is, a laminate having a structure in which the adherend is covered with the patterned adhesive sheet was produced. . In Table 1, the value of the adhesive force after 12 hours at room temperature of the adhesive sheet D1 as the adhesive force during the partial removal process of Production Example 1, and the value of the adhesive force after heating the adhesive sheet D1 as the adhesive force of the laminate.

(Production Example 2)

Production Example, except that the adhesive sheet D2 was used instead of the adhesive sheet D1, and the stimulus added in the adhesive strength increasing step was changed from heating to the above-mentioned UV irradiation (approximately 365 nm in wavelength, 2000 mJ/cm 2 of light). A laminate was prepared in the same procedure as 1. Table 1 shows the adhesive strength value after 12 hours at room temperature of the adhesive sheet D2 as the adhesive force during the partial removal process of Production Example 2, and the adhesive strength value after UV irradiation of the adhesive sheet D2 as the adhesive strength of the laminate.

(Production Examples 3 and 4)

Using the pressure-sensitive adhesive sheet shown in Table 1, after the cutting step, neither the above-mentioned heating and UV irradiation were performed, but instead the above-mentioned standard until the elapsed time from the affix to the adherend became 24 hours. It was left under the environment. For other points, a laminate was produced by the same procedure as in Production Example 1. In Table 1, values of the adhesive force after 12 hours at room temperature of each pressure-sensitive adhesive sheet as the adhesive force at the time of partial removal processes of Production Examples 3 and 4, and values of the adhesive force after 24 hours at room temperature of each pressure-sensitive adhesive sheet as a pressure-sensitive adhesive force of the laminate are described. .

(Production Example 5)

In Production Example 1, the above-mentioned heating (80° C., 5 minutes) was carried out about 11 hours after the adhesive sheet D1 was adhered to the adherend, and the elapsed time after the adhesive sheet D1 was adhered to the adherend was about 12 hours. After keeping at room temperature until time, some removal steps were performed. A laminate was manufactured in the same manner as in Production Example 1 for other points. Table 1 shows the values of the adhesive strength after heating of the adhesive sheet D2 as the adhesive strength during the partial removal process of Production Example 5.

(Production Examples 6 and 7)

The adhesive sheets D1 and D2 were adhered to the adherend in the same manner as in Production Example 1, and left in a fluorescent lamp for about 24 hours in a room maintained in the above standard environment, followed by a similar cut process, followed by a partial removal process. . Thereafter, the laminates according to Production Examples 6 and 7 were obtained by holding the adhesive sheets D1 and D2 on the adherend under a fluorescent lamp indoors in the above standard environment until the elapsed time reached 4 weeks. In Table 1, the values of the adhesive force after 24 hours at room temperature of each adhesive sheet as the adhesive force at the time of the partial removal process of Production Examples 6 and 7, and the values of the adhesive force after 4 weeks of each adhesive sheet are described as the adhesive force of the laminate.

(Evaluation of slit part removal)

In some removal steps of each production example, when peeling the second region from the adherend, "G" (pattern formability is good) when deformation such as elongation is not observed in the adherend, "P" when deformation is confirmed It was evaluated as (insufficient pattern workability). Table 1 shows the results.

In addition, in Production Examples 4 and 5, peeling of the second region could not be appropriately performed, so the following durability test was not performed. In addition, in any case of Preparation Examples 1 to 3 and 6 and 7, no residual adhesive or contamination of the adherend to the adherend was observed when peeling the second region.

(Durability test)

For the laminates obtained in Production Examples 1 to 3 and 6 and 7, using a surface-shaped non-load U-shaped stretching tester "DLDM111LH" manufactured by Yuasa Systems Equipment Co., Ltd. and a jig (surface-shaped non-load U-shaped stretching test jig), The durability test was performed under the conditions of a stretching speed of 30 rpm, a bending radius of 3 mm, and stretching times of 100 times.

Specifically, as shown in FIG. 6, after fixing both ends x and y of the sample 60 to the clamp portions 61 and 62 of the tester with double-sided tape (not shown), under the above conditions, the sample ( 60) From the state of this flat surface, the elastic sheet was bent in a U-shape with a bending radius of 3 mm with the adhesive sheet side inward. When bending the sample 60, both ends x and y of the sample 60 are brought into contact by the operation of the clamp, and the other portions of the sample 60 are positively provided by plate portions 63 and 64 which are separately installed. It was picked up from the outside with no load.

The state of the sample after 100 stretches was visually observed, and evaluated as ``G'' (good durability) when excitation was not seen between the adhesive sheet and the adherend, and ``P'' (insufficient durability) when excitation was seen. Did. Table 1 shows the results.

As shown in Table 1, in Production Examples 1, 2, and 4 to 7 regarding the production of a laminate having an adhesive strength of 5N/25mm, Preparation Examples 1 and 2 were partially removed before the adhesive strength exceeded 2N/25mm. , 6 and 7, the peelability of the second region in some removal processes was good, and the produced laminate exhibited good durability. In contrast, in Production Example 3, the obtained laminate had low durability, and in Production Examples 4 and 5, there was difficulty in peelability of the second region in some removal processes.

As mentioned above, although the specific example of this invention was demonstrated in detail, these are only illustrations and do not limit a claim. The technology described in the claims includes various modifications and changes to the specific examples exemplified above.

1: laminate
10: adherend
10A: Surface
20: adhesive sheet
21: first area
21A, 21B: Adhesive piece
22: second zone
202: base layer
204: adhesive layer
50: laminate manufacturing apparatus
51: sticking mechanism
52: cut mechanism
53: peeling mechanism

Claims (9)

A method of manufacturing a laminate comprising an adherend and an adhesive piece partially covering the adherend, wherein the adhesion strength of the adhesive piece to the adherend is 5N/25mm or more,
A sticking step of attaching a pressure-sensitive adhesive sheet comprising a base material layer and a pressure-sensitive adhesive layer laminated on at least the side of said adherend to said adherend;
A cutting step of cutting the boundary between the first region constituting the adhesive piece and the second region not constituting the adhesive piece of the adhesive sheet; And
A partial removal process of removing and removing the second region from the adherend while leaving the first region on the adherend;
And in this order,
Here, the partial removal process is performed before the adhesive strength of the adhesive sheet to the adherend exceeds 2N/25mm,
After the partial removal step, the ultraviolet ray irradiation treatment is performed, so that the adhesive strength of the first region to the adherend is 5 N/25 mm or more. The method for producing a laminate according to claim 1, wherein the adhesive sheet having an adhesive strength of 2 N/25 mm or less after 24 hours at 23° C. after bonding to polyimide is used. According to claim 1 or claim 2, The pressure-sensitive adhesive layer is made of a photocurable composition comprising a base polymer and a photocuring agent,
The photocuring agent is a polyfunctional (meth)acrylate,
The content of the photocuring agent is 1 part by weight or more and 50 parts by weight or less with respect to 100 parts by weight of the base polymer. The thickness of the said adhesive sheet is 30 micrometers or more, The thickness Ts of the said base material layer is 2 times or more of the thickness Ta of the said adhesive layer, The laminated body manufacturing method of any one of Claims 1-3. The method for manufacturing a laminate according to any one of claims 1 to 4, wherein the second region is set such that at least one end of the second region reaches the end of the adhesive sheet. The method according to claim 5, wherein the second region has a shape in which one end reaching the end of the pressure-sensitive adhesive sheet is widened toward the edge of the pressure-sensitive adhesive sheet. The method for manufacturing a laminate according to any one of claims 1 to 6, wherein the pressure-sensitive adhesive sheet used in the pasting step has an area of 2500 cm 2 or more and a short side having a length of 50 cm or more. The pressure-sensitive adhesive sheet and the adherend used in the attaching process are those comprising a plurality of units corresponding to the laminate, according to any one of claims 1 to 7,
A process performed after the pasting step, further comprising a dividing step of dividing the adhesive sheet and the adherend into units. An apparatus for carrying out the manufacturing method according to any one of claims 1 to 8,
A sticking mechanism for sticking the adhesive sheet,
A cutting mechanism for cutting the adhesive sheet;
Peeling mechanism for peeling the second region of the adhesive sheet
A laminate manufacturing apparatus comprising a.

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